Higher Computing Science. Software Design and Development

Transcription

1 Higher Computing Science Software Design and Development Programming with Visual Studio

2 CONTENTS Topic 1 Topic 2 Topic 3 Topic 4 Topic 5 Topic 6 Topic 7 Topic 8 Topic 9 Getting started Strings and Pre-Defined Functions Selection 1-D Arrays User-defined functions Parameter passing Standard Algorithms Reading from a sequential file Using records Higher Computing Science 2

3 TOPIC 1 GETTING STARTED You will have used a variety of different data types in the Nat 5 programming unit. These are: Integer - stores whole numbers Single String Boolean - stores real numbers (numbers with a decimal point in them) - stores alphanumeric characters (letters / symbols / numbers) - stores one of two values: True or False Task 1: Wages program - Using variables: Real (single) Program specification Wages calculator Design and write a program that asks the user to enter their hourly rate and the number of hours worked. The total pay should be calculated and displayed. FORM DESIGN PROPERTIES HEADING Label: Name is lblheading Text is Real Numbers EXIT Button: Name is cmdexit Text is EXIT CLEAR button: Name is cmdclear Text is CLEAR START button: Name is cmdstart Text is START LISTBOX1: Name is listbox1 DESIGN 1. Take in pay details 2. Calculate wages Refine Step 1: Take in pay details 1.1 Ask for hourly rate. 1.2 Display hourly rate. 1.3 Ask for number of hours worked. 1.4 Display number of hours worked. Refine Step 2: calculate wages 2.1 Total pay = hourly rate * hours worked 2.2 Display total pay Higher Computing Science 3

4 TOPIC 1 GETTING STARTED CODE Public Class Form1 'Task 1: Real Variables program to calculate the total pay from hours worked and work rate 'set the data types of the global variables required in the program Dim hours_per_week, hourly_rate, total_pay As Single Private Sub cmdstart_click(sender As Object, e As EventArgs) Handles cmdstart.click 'main steps to calculate total pay take_in_details() calculate_wage() Private Sub take_in_details() ' Step 1: take in hourly rate and hours worked and convert to a value hourly_rate = Val(InputBox("Please enter your hourly rate.")) ListBox1.Items.Add("The hourly rate is " & hourly_rate) hours_per_week = Val(InputBox("Please enter your hours worked this week.")) ListBox1.Items.Add("The number of hours worked is " & hours_per_week) Private Sub calculate_wage() ' Step 2: calculate and display the total wage total_pay = hourly_rate * hours_per_week ListBox1.Items.Add("") ' display a blank line ListBox1.Items.Add("The total pay for the week is " & total_pay) Private Sub cmdclear_click(sender As Object, e As EventArgs) Handles cmdclear.click 'clear the contents of the list box ListBox1.Items.Clear() Private Sub cmdexit_click(sender As Object, e As EventArgs) Handles cmdexit.click End End Class Load and run the program called Higher Task1 Real. Higher Computing Science 4

5 OUTPUT TOPIC 1 GETTING STARTED Run your program with the test data below. You will notice from the output that the total pay is not displayed properly: The pay has 3 decimal places The pay does not have a pound sign Formatting output In your calculate_wage procedure change the line that displays the wage to this: ListBox1.Items.Add("The total pay for the week is " & Format(total_pay, ".000")) Copy the table below and adapt your program to the different formats shown. Decsribe the output that each format command produces: Format Command Format(average, ".000") Format(average, "000.0") Format(average, "###.0") Format(average, "fixed") Format(average, "currency") Format(average, "percent") Description of this function Higher Computing Science 5

6 TOPIC 1 GETTING STARTED Task 2: Ask a question - Using Variables: Boolean Program specification Ask a question Design and write a program that asks the user to enter the answer to a question. The user will be told whether they are correct or wrong. FORM DESIGN PROPERTIES HEADING Label: Name is lblheading Text is Boolean Variables EXIT Button: Name is cmdexit Text is EXIT CLEAR button: Name is cmdclear Text is CLEAR START button: Name is cmdstart Text is START LISTBOX1: Name is listbox1 DESIGN 1. Ask question() 2. Check answer() 3. Display result() Refine Step 1: Ask Question 1.1 set correct to False 1.2 ask for answer to question what is capital of Norway?. 1.3 Display user s answer Refine Step 2: check answer is correct 2.1 if answer is Oslo 2.2 set correct to True 2.3 end if Refine Step 3: Ask Question 3.1 If correct is True 3.2 display well done message 3.3 Else 3.4 Display wrong message 3.5 End if Higher Computing Science 6

7 TOPIC 1 GETTING STARTED CODE Public Class Form1 'Task 2: program with Boolean value 'Quiz program which asks for the capital of Norway 'set the data types of the global variables required in the program Dim answer As String Dim correct As Boolean Private Sub cmdstart_click(sender As Object, e As EventArgs) Handles cmdstart.click 'main steps to calculate total pay Ask_question() Check_answer() Display_message() Private Sub ask_question() ' ask the user the question and display their answer correct = False answer = InputBox("What is the capital city of Norway?") ListBox1.Items.Add("The answer you gave is " & answer) ListBox1.Items.Add("") Private Sub check_answer() ' check if the users answer is correct If answer = "Oslo" Then correct = True Private Sub display_message() ' display an appropriate message to the user If correct = True Then ListBox1.Items.Add("Your answer is correct - well done!") Else ListBox1.Items.Add("Your answer is not correct") End If Private Sub cmdclear_click(sender As Object, e As EventArgs) Handles cmdclear.click 'clear the contents of the list box ListBox1.Items.Clear() Private Sub cmdexit_click(sender As Object, e As EventArgs) Handles cmdexit.click End End Class Load and run the program called Higher Task 2 Boolean Higher Computing Science 7

8 TOPIC 1 GETTING STARTED OUTPUT Run your program with the test data below: Task 3: Charity Collection Procedures and formatting Problem: Three friends have been collecting money for charity. A local company has offered to add a donation based on the total amount they manage to raise. Write a program that allows the friends to enter their individual amounts. The program should then add the three amounts and store the total. The following decisions on the donation from the company are made: a) any amount raised less than 1000 has a 100 bonus (for example 345 raised = 445 total) b) the company will double the amount raised between (and including) 1000 and 2000 (for example 1282 raised = 2564 total) c) if the amount is over 2000 the initial 2000 is doubled but any amount after that is not (for example 2054 raised = 2* = 4054 total) Create a design for your Form and for your Code. Show this to your teacher before you implement this program. Typical Inputs and Output Higher Computing Science 8

9 TOPIC 2 STRINGS & PRE-DEFINED FUNCTIONS Topic 2 - Working with Strings Visual Studio provides a number of useful pre-defined functions for manipulating strings. Name How it works What it does Example Input(s) Output Len String Integer calculates the number of characters in a string Letters = Len( blob ) will result in Letters = 4 Ucase String String converts lower-case characters into upper-case characters Lcase String String converts upper-case characters into lower-case characters Asc String Integer Returns the ASCII value of a character Chr Integer String takes an ASCII value and returns the corresponding character String_in = Ucase( blob ) will result in String_in = BLOB String_in = Lcase( XX ) will result in String_in = xx Ascii-no = Asc( A ) will result in Ascii_no = 65 Letter = Chr(65) will result in Letter = A Left String Integer String Extracts a sub-string from a string Part = Left( Word, 3) will result in Part = Wor Right String Integer String Extracts a sub-string from a string Part = Right( Word, 2) will result in Part = rd Mid String Integer Integer String extracts a sub-string from a string Part = Mid$( Word, 2, 3) will result in Part = ord NOTE: Every function above has one or more inputs to the functions BUT every function has only ONE OUTPUT!!! Higher Computing Science 9

10 TOPIC 2 STRINGS & PRE-DEFINED FUNCTIONS Task 4: String functions Program specification The program will ask the user to enter a name and will then carry out a series of string operations on the name. FORM DESIGN PROPERTIES HEADING Label: Name is lblheading Text is Pre-Defined String Functions EXIT Button: Name is cmdexit Text is EXIT CLEAR button: Name is cmdclear Text is CLEAR LowerCase button: Name is cmdlower Text is Lower case UpperCase button: Name is cmdupper Text is Upper case Left button: Name is cmd Left Text is Left Right button: Name is cmdright Text is Right Middlebutton: Name is cmdmiddle Text is Middle Capitalise button: Name is cmdcapfirst Text is Capitalise First Convert button: Name is cmdconvert Text is Convert first to ASCII LISTBOX1: Name is listbox1 Higher Computing Science 10

11 TOPIC 2 STRINGS & PRE-DEFINED FUNCTIONS DESIGN Lowercase 1. Read in originalname 2. Change originalname to lowercase and store in newname 3. Display originalname 4. Display newname Uppercase 1. Read in originalname 2. Change originalname to uppercase and store in newname 3. Display originalname 4. Display newname Left 1. Read in originalname 2. Store the left 2 characters in newname 3. Display originalname 4. Display newname Right 1. Read in originalname 2. Store the right 2 characters in newname 3. Display originalname 4. Display newname Middle 1. Read in originalname 2. Get the length of originalname 3. Store the middle two characters in newname 4. Display length 5. Display originalname 6. Display newname Higher Computing Science 11

12 TOPIC 2 STRINGS & PRE-DEFINED FUNCTIONS Capitalise First 1. Read in originalname 2. Get the length of original name 3. Store the first character in firstletter 4. Store the rest of the characters in restofname 5. Make firstletter a capital and store it in capital 6. Concatenate the capital and the restofname 7. Display length 8. Display original name 9. Display new name Convert to Ascii 1. Read in originalname 2. Store the first character in firstletter 3. Convert firstletter to an Ascii value and store it in letterasascii 4. Display original name 5. Display first letter 6. Display first letter as Ascii CODE Public Class Form1 'Task 3 : program with pre-defined string functions 'set the data types of the global variables required in the program Dim originalname, newname, firstletter, restofname, capital As String Dim letterasascii, length As Integer Private Sub cmdlower_click(sender As Object, e As EventArgs) Handles cmdlower.click ' convert the name to lower case letters originalname = InputBox("Please enter a name") newname = LCase(originalname) ListBox1.Items.Add("the original name is : " & originalname) ListBox1.Items.Add("the new name name is :" & newname) ListBox1.Items.Add("") Private Sub cmdupper_click(sender As Object, e As EventArgs) Handles cmdupper.click ' convert the name to upper case letters originalname = InputBox("Please enter a name") newname = UCase(originalname) ListBox1.Items.Add("the original name is :" & originalname) ListBox1.Items.Add("the new name name is : " & newname) ListBox1.Items.Add("") Higher Computing Science 12

13 TOPIC 2 STRINGS & PRE-DEFINED FUNCTIONS Private Sub cmdleft_click(sender As Object, e As EventArgs) Handles cmdleft.click ' extract the first character on the left originalname = InputBox("Please enter a name") newname = Microsoft.VisualBasic.Left(originalname, 2) ListBox1.Items.Add("the original name is : " & originalname) ListBox1.Items.Add("the first two characters are : " & newname) ListBox1.Items.Add("") Private Sub cmdright_click(sender As Object, e As EventArgs) Handles cmdright.click ' extract the last character from the right originalname = InputBox("Please enter a name") newname = Microsoft.VisualBasic.Right(originalname, 2) ListBox1.Items.Add("the original name is : " & originalname) ListBox1.Items.Add("the last two characters are : " & newname) ListBox1.Items.Add("") Private Sub cmdmiddle_click(sender As Object, e As EventArgs) Handles cmdmiddle.click ' extract the middle two characters of the name originalname = InputBox("Please enter a name") length = Len(originalname) newname = Microsoft.VisualBasic.Mid(originalname, length / 2, 2) ListBox1.Items.Add("The length of the original name is " & length) ListBox1.Items.Add("the original name is : " & originalname) ListBox1.Items.Add("the middle two characters are : " & newname) ListBox1.Items.Add("") Private Sub cmdcapfirst_click(sender As Object, e As EventArgs) Handles cmdcapfirst.click ' extract the first letter of the name and capitalise it originalname = InputBox("Please enter a name") length = Len(originalname) firstletter = Microsoft.VisualBasic.Left(originalname, 1) restofname = Microsoft.VisualBasic.Right(originalname, length - 1) capital = UCase(firstletter) newname = capital + restofname ListBox1.Items.Add("The length of the original name is " & length) ListBox1.Items.Add("the original name is : " & originalname) ListBox1.Items.Add("The new name with a capital letter is : " & newname) ListBox1.Items.Add("") Private Sub cmdconvertascii_click(sender As Object, e As EventArgs) Handles cmdconvertascii.click ' extract the first character of the name and convert to ASCII originalname = InputBox("Please enter a name") firstletter = Microsoft.VisualBasic.Left(originalname, 1) letterasascii = Microsoft.VisualBasic.Asc(firstletter) ListBox1.Items.Add("the original name is : " & originalname) ListBox1.Items.Add("The first letter of name is : " & firstletter) ListBox1.Items.Add("The first letter as ASCII is : " & letterasascii) ListBox1.Items.Add("") End Class Load and run the program called Higher Task 4 String functions. Higher Computing Science 13

14 TOPIC 2 STRINGS & PRE-DEFINED FUNCTIONS OUTPUT Run your program with the test data below: Lower case, Upper case, Left, Right: Middle, Capitalise First, Convert first to ASCII: Higher Computing Science 14

15 TOPIC 2 STRINGS & PRE-DEFINED FUNCTIONS Task 5: Devising User IDs String functions Problem: A program is required which will automatically generate a password from information provided by the user. The program should generate the password from the first letter of their first name, second letter of their surname, last two letters of their birth month converted to upper case, second and third letters of their favourite colour, first 3 letters of their street name, the second-last character in their name then converted to an ASCII value and finishing with the letters VB. For example, Brenda McSporran, born in NovembER, likes the colour green lives in Market Place, second last letter is a and converted to 97, so her password will be BcERreMar97VB. Create a design for your Form and for your Code. Show this to your teacher before you implement this program. Pre-defined Numeric Functions There are pre-defined functions that work in a mathematical way. These include: name what it does example Rnd generates a random number between 0 and 1 X = Rnd * 10 Int Round returns the whole number part of a real number Rounds a value to a specified number of decimal places Answer = Int(3.24) returns Answer = 3 Answer = Round(3.24, 1) returns Answer = 3.2 Val Is used to convert a string to a numeric value Number=Val(txtInput.text) Higher Computing Science 15

16 TOPIC 2 STRINGS & PRE-DEFINED FUNCTIONS Task 6: Using Pre-defined Numeric Functions Problem specification Create a program which will generate a random number. The program will use the INT function on a random number and also the ROUND function. FORM DESIGN PROPERTIES HEADING Label: Name: lblheading Text: Pre-Defined Numeric Functions EXIT Button: Name: cmdexit Text: EXIT CLEAR button: Name: cmdclear Text: CLEAR Random button: Name: cmdrandom Text: Random Number Int button: Name: cmdint Text: Int Roundbutton: Name: cmdround Text: Round ListBox: Name: listbox1 Higher Computing Science 16

17 TOPIC 2 STRINGS & PRE-DEFINED FUNCTIONS DESIGN Random Number 1. Generate random number 2. Display random number 3. Display blank line Int 1. Generate random number 2. Apply INT function to remove decimal part of random number and store as result 3. Display random number 4. Display result 5. Display blank line Round 1. Generate random number 2. Apply ROUND function to round random number to one decimal place and store as result 3. Display random number 4. Display result 5. Display blank line Higher Computing Science 17

18 TOPIC 2 STRINGS & PRE-DEFINED FUNCTIONS CODE Public Class Form1 'Task 4: program with pre-defined maths functions Dim randomnumber, result As Single Private Sub cmdrandom_click(sender As Object, e As EventArgs) Handles cmdrandom.click ' generate a random number between 0 and 1 Randomize() randomnumber = Microsoft.VisualBasic.Rnd() ListBox1.Items.Add("the random number generated was : " & randomnumber) ListBox1.Items.Add("") Private Sub cmdint_click(sender As Object, e As EventArgs) Handles cmdint.click 'remove the decimal part of a number Randomize() randomnumber = Microsoft.VisualBasic.Rnd() * 10 result = Int(randomnumber) ListBox1.Items.Add("the random number multiplied by 10 is : " & randomnumber) ListBox1.Items.Add("INT converts this number to : " & result) ListBox1.Items.Add("") Private Sub cmdround_click(sender As Object, e As EventArgs) Handles cmdround.click 'round a random number to one decimal place Randomize() randomnumber = Microsoft.VisualBasic.Rnd() result = Math.Round(randomnumber, 1) ListBox1.Items.Add("the random number generated was : " & randomnumber) ListBox1.Items.Add("Rounded to one decimal place : " & result) ListBox1.Items.Add("") Private Sub cmdclear_click(sender As Object, e As EventArgs) Handles cmdclear.click ListBox1.Items.Clear() End Class Load and run Higher Task 6 Maths Functions. Higher Computing Science 18

19 TOPIC 2 STRINGS & PRE-DEFINED FUNCTIONS OUTPUT Run your program a few times like the test runs below. Task 7: Painting a fence Procedures, rounding and formatting Problem: The program should calculate the number of tins of paint to paint a rectangular fence and the total cost of buying the tins. The user should enter the dimensions of the fence (the length and height in metres), the cost of one tin of paint and the coverage factor for one tin of paint (how many metres squared can be painted). Both the front and the back of the fence will need to be painted. The program should display the following details: The total area to be painted (to one decimal place) The number of tines required (rounded up to a whole number) The total cost of buying the tins (formatted as currency). Create a design for your Form and for your Code. Show this to your teacher before you implement this program. Higher Computing Science 19

20 TOPIC TOPIC 1 GETTING 3 - SELECTION STARTED Topic 3 - Selection using CASE A Case statement is an alternative to using multiple IF statements. This method has the same outcome but requires less code and is easier to read. Task 8: Assign a grade Case statement Problem specification Design and write a program that asks the user to enter their mark. A grade is assigned as follows:- 80 or over is a grade 1, 60 to 79 is a grade 2, 40 to 59 is a grade 3, 20 to 39 is a grade 4, 10 to 19 is a grade 5, less than 10 is a grade 6. The grade should be displayed. FORM DESIGN PROPERTIES HEADING Label: Name: lblheading Text: Case Statement EXIT Button: Name: cmdexit Text: EXIT CLEAR button: Name: cmdclear Text: CLEAR START button: Name: cmdstart Text: START LISTBOX1: Name: listbox1 Higher Computing Science 20

21 TOPIC TOPIC 1 GETTING 3 - SELECTION STARTED DESIGN MAIN STEPS 1. Take in mark() 2. Display grade() DESIGN - REFINEMENTS Refine Step 1: Take in Mark () 1.1 Read in the pupils mark 1.2 In the case of mark 1.3 Greater than or equal to Grade is Greater than or equal to Grade is Greater than or equal to Grade is Greater than or equal to Grade is Greater than or equal to Grade is Less than Grade is End Case Statement Refine Step 2: Display Grade () 2.1 Display the mark 2.2 Display the grade 2.3 Display a blank line Higher Computing Science 21

22 TOPIC TOPIC 1 GETTING 3 - SELECTION STARTED CODE Public Class Form1 'task 3.1 Using a case statement to decide on a student grade Dim mark, grade As Integer Private Sub cmdstart_click(sender As Object, e As EventArgs) Handles cmdstart.click take_in_mark() display_grade() Private Sub take_in_mark() ' ask user to enter the mark out of 100 mark = Val(InputBox("Please enter pupil's mark out of 100")) 'decide on an appropriate grade Select Case mark Case Is >= 80 grade = 1 Case Is >= 60 grade = 2 Case Is >= 40 grade = 3 Case Is >= 20 grade = 4 Case Is >= 10 grade = 5 Case Is < 10 grade = 6 End Select Private Sub display_grade() ' display the pupil's mark and grade ListBox1.Items.Add("The pupil's mark is " & mark) ListBox1.Items.Add("Their grade is " & grade) ListBox1.Items.Add("") End Class OUTPUT Test your program with sample output similar to below: Load and run Higher Task 8 Assign a grade. Higher Computing Science 22

23 TOPIC TOPIC 1 GETTING 3 - SELECTION STARTED Task 9: Posting a Package Case statement Design, implement and test a program to calculate the cost of posting a package by first class mail, based on the following table: Weight up to and including: Cost 100g 42p 300g 99p 450g g g g g 3.45 each extra 250g add 86p Create a design for your Form and for your Code. Show this to your teacher before you implement this program. Theory Task 1: Error detection Ask your teacher for a printed copy of this task. Higher Computing Science 23

24 Topic 4: Arrays TOPIC 4 - ARRAYS Task 10: Store 10 marks - Fill an array using a For Loop Problem specification Design and write a program that asks the user to enter 10 marks. The marks should then be displayed. FORM DESIGN PROPERTIES HEADING Label: Name: lblheading Text: Fill an Array EXIT Button: Name: cmdexit Text: EXIT CLEAR button: Name: cmdclear Text: CLEAR START button: Name: cmdstart Text: START LISTBOX1: Name: listbox1 Higher Computing Science 24

25 TOPIC 4 - ARRAYS DESIGN 1. Take in Marks() 2. Display Marks() Refine Step 1 Take in Marks 1.1 repeat 10 times 1.2 read in current mark into correct location in array 1.3 end loop Refine Step 2 Display Marks 2.1 Display heading 2.2 Display blank line 2.3 Repeat 10 times 2.4 Display current mark 2.5 End loop CODE Public Class Form1 ' Topic 4: Filling a array within a fixed loop Dim mark(9) As Integer Dim pupil As Integer Private Sub cmdstart_click(sender As Object, e As EventArgs) Handles cmdstart.click 'main steps of the problem take_in_marks() display_marks() Private Sub take_in_marks() 'ask for 10 marks For pupil = 0 To 9 mark(pupil) = Val(InputBox("Please enter the mark for pupil " & pupil + 1)) Next pupil Private Sub display_marks() 'display the marks in the listbox End Class ListBox1.Items.Add("Here are the marks for the class") ListBox1.Items.Add("") For pupil = 0 To 9 ListBox1.Items.Add("Pupil " & pupil + 1 & "- mark is " & mark(pupil)) Next pupil Higher Computing Science 25

26 TOPIC 4 - ARRAYS Load and run the program called Higher Task 10 Fill an array. OUTPUT Theory Task 2: Error detection Ask your teacher for a printed copy of this task. Task 11: Lottery Winner Using arrays & RND function. Problem Specification Design, implement and test a program to do the following: The program should prompt the user to enter 10 names and 4 different prizes. The program should select a lucky winner at random and assign them a prize also chosen at random. The program should display all ten possible winners and all 4 possible prizes. It should also display the name of the winner and the chosen prize. Create a design for your Form and for your Code. Show this to your teacher before you implement this program Higher Computing Science 26

27 TOPIC TOPIC 1 5 GETTING PARAMETER STARTEDPASSING Topic 5: Parameter Passing This section of the course shows algorithms including data flow as well as programs that use procedures. Data Flow: In/out In is the equivalent of ByRef is the equivalent of ByVal Task 12: Area of a rectangle Parameter passing Problem specification Design and write a program that asks the user to enter a length and a breadth of a rectangle. The area of the rectangle is calculated and then displayed. FORM DESIGN PROPERTIES HEADING Label: Name: lblheading Text: Area of a rectangle EXIT Button: Name: cmdexit Text: EXIT CLEAR button: Name: cmdclear Text: CLEAR START button: Name: cmdstart Text: START LISTBOX1: Name: listbox1 Higher Computing Science 27

28 TOPIC TOPIC 1 5 GETTING PARAMETER STARTEDPASSING DESIGN MAIN STEPS 1 get values from user() in/out: length, breadth 2 calculate the area() in: length, breadth in/out: area 3 display the area () in: area CODE DESIGN REFINEMENTS refine step 1 get values from user in/out: length, breadth 1.1 Read in the length 1.2 Display the length 1.3 Read in the breadth 1.4 Display the breadth refine step 2 calculate the area in: length, breadth in/out: area 2.1 multiply length by breadth to give area refine step 3 display the area in: area 1.1 display a blank line 1.2 display a message to the use giving the area Higher Computing Science 28

29 TOPIC TOPIC 1 5 GETTING PARAMETER STARTEDPASSING CODE Public Class Form1 ' this program calculates the area of a rectangle using parameter passing Private Sub cmdstart_click(sender As Object, e As EventArgs) Handles cmdstart.click 'the main steps of the problem declare the parameter data types Dim length, breadth, area As Single getvalues(length, breadth) calculatearea(length, breadth, area) displayarea(area) Private Sub getvalues(byref length, ByRef breadth) ' ask the user to enter the dimensions of the rectangle length = Val(InputBox("Please enter the length of the rectangle (in centimetres)")) ListBox1.Items.Add("The length is " & length & "cm") breadth = Val(InputBox("Please enter the breadth of the rectangle (in centimetres)")) ListBox1.Items.Add("The breadth is " & breadth & "cm") Private Sub calculatearea(byval length, ByVal breadth, ByRef area) ' this module will calculate the area area = length * breadth Private Sub displayarea(byval area) ' this module will display the area ListBox1.Items.Add("") ListBox1.Items.Add("The area of the rectangle is " & area & "cm squared") End Class Load and run Higher Task 12 Area of a rectangle. OUTPUT Test your program with sample output similar to below: Higher Computing Science 29

30 TOPIC TOPIC 1 5 GETTING PARAMETER STARTEDPASSING Task 13: Estimate Grades Parameter passing Problem specification Design, implement and test a program to do the following: The program will estimate a pupil s grade for their Nat5 Computing Science exam based on a mark from their prelim and their coursework total. Their prelim mark is out of 90 and their coursework is out of 60. The total is converted to a percentage and the following estimates are applied: >= 85% = Band 1 >= 70% = Band 2 >= 65% = Band 3 >= 60% = Band 4 >= 55% = Band 5 >= 50% = Band 6 >= 45% = Band 7 <45% = Band 8 Your program should display the total mark out of 150, their percentage and their Band estimate. Create a design for your Form and for your Code showing the data flow for the problem. Show this to your teacher before you implement this program. Higher Computing Science 30

31 TOPIC 6 USER-DEFINED FUNCTIONS Topic 6: User-defined Functions Pre-defined functions (like LEN) are already made for us. If we want to create a function we will use again and again, we create a user-defined function. Functions can input several parameters but only ever return one value. Functions are different from procedures that can input several parameters and may also return many parameters. Task 14: Calculate an area Using a function Problem specification Design and write a program that asks the user to enter the radius of a circle. The area is then calculated and displayed. FORM DESIGN PROPERTIES HEADING Label: Name: lblheading Text: Area of a circle (user-defined Function) EXIT Button: Name: cmdexit Text: EXIT CLEAR button: Name: cmdclear Text: CLEAR START button: Name: cmdstart Text: START LISTBOX1: Name: listbox1 DESIGN MAIN STEPS 1. get radius() in/out: radius 2. calculate and display the area() in: radius CODE DESIGN REFINEMENTS Refine step 1 get radius from user 1.1 Read in the radius 1.2 Display the radius in/out: radius Higher Computing Science 31

32 TOPIC 6 USER-DEFINED FUNCTIONS Refine step 2 calculate and display the area 2.1 calculate area 2.2 display area in: radius Refine Function: get Area display the area in: radius 1. area = radius ^ 2 * return area CODE Public Class Form1 'this program calculates the area of a circle 'this version uses a user-defined function to calculate the area Private Sub cmdstart_click(sender As Object, e As EventArgs) Handles cmdstart.click 'this contains the main steps of the problem 'declare parameter data type Dim radius As Single get_radius(radius) calculate_and_display(radius) Private Sub get_radius(byref radius) ' this module will ask the user to enter the radius radius = Val(InputBox("Please enter the radius of the circle in cm")) ListBox1.Items.Add("The radius of the circle is " & radius & "cm") Private Sub calculate_and_display(byval radius) Dim area As Single area = get_area(radius) ListBox1.Items.Add("The area is " & area & "cm squared") Function get_area(radius) As Single Dim area As Single area = math.round(radius ^ 2 * 3.14,2) Return area End Function End Class Load and run Higher Task 14 Area using function. OUTPUT Test your program with the following test data: Test Type of Test Test data Expected Result 1 Normal Radius = 5 Area = Normal Radius = 6.7 Area = Extreme Radius = Area = Higher Computing Science 32

33 TOPIC 6 USER-DEFINED FUNCTIONS Task 15: Input Validation Function Problem specification Design a program which will ask the user to enter two numbers between 1 and 10. The program will then find the sum of these numbers. Inputs from the user must be validated. FORM DESIGN PROPERTIES HEADING Label: Name: lblheading Text: Validation using a Function EXIT Button: Name: cmdexit Text: EXIT CLEAR button: Name: cmdclear Text: CLEAR START button: Name: cmdstart Text: START LISTBOX1: Name: listbox1 DESIGN MAIN STEPS 1 get_numbers() in/out: num1, num2 2 calculate and display total() in: num1, num2 DESIGN REFINEMENTS Refine step 1 get numbers 1.1 Validate number 1 using function 1.2 Validate number 2 using function in/out: num1, num2 Higher Computing Science 33

34 TOPIC 6 USER-DEFINED FUNCTIONS Refine step 2 calculate and display total 2.1 calculate sum of number 1 and number calculate and display answer in: radius Refine Function: get valid number in: prompt, low, high out: number 1. ask the user to enter a number between low and high 2. Loop while the number is less than low or greater than high 3. Display an error message to the user 4. Ask the user to re-enter the number 5. End loop 6. return number CODE Public Class Form1 'program using a function to validate inputs from user Private Sub cmdstart_click(sender As Object, e As EventArgs) Handles cmdstart.click 'declare data flow parameters Dim num1, num2 As Integer 'main steps get_values(num1, num2) calculate_and_display_total(num1, num2) Private Sub get_values(byref num1, ByRef num2) 'procudeure to input numbers from user num1 = get_valid_number("please enter a number between, 1, 10) num2 = get_valid_number("please enter a number between, 1, 10) Private Sub calculate_and_display_total(byval num1, ByVal num2) 'procedure to calculate and display values 'declare local variable Dim answer As Integer answer = num1 + num2 ListBox1.Items.Add(num1 & " + " & num2 & " = " & answer) Function get_valid_number(byval prompt, byval low, byval high) As Integer 'function used to validate a number between 2 boundaries Dim number as integer number = Val(InputBox(prompt & low & and & high)) Do While number < low Or number > high MsgBox("That number is invalid. Please try again") number = Val(InputBox(prompt & low & and & high)) Loop Return number End Function End Class Load and run Higher Task 15 Input Validation Higher Computing Science 34

35 TOPIC 6 USER-DEFINED FUNCTIONS OUTPUT Test your program with the following test data: Test Type of Test Test data Expected Result 1 Normal Num1 = 4 num2 = = 11 2 Normal Num1 = 8 num2 = = 13 3 Extreme Num1 = 1 num2 = = 11 4 Extreme Num1 = 2 num2 = Exceptional Num1 = 14 num2 = 7 Error message for num1 6 Exceptional Num1 = 4 num2 = 78 Error message for num2 Task 16: Input Validation User defined functions Problem specification Design, implement and test a program to do the following: The user should enter 3 different values and each should be validated as shown: I. prompt the user to enter either a yes or a no. the program should also accept yes, no, yes, NO, no etc II. III. prompt the user to enter a telephone number. The program should only accept a number starting with the digit 0 and with a total of 11 digits. Assume no spaces are allowed. Prompt the user to enter a password which can include any character except for a space, and must be more than 6 characters long. Create a design for your Form and for your Code. Show this to your teacher before you implement this program. Higher Computing Science 35

36 TOPIC 7 STANDARD ALGORITHMS Topic 7: Standard Algorithms In the design and development of software, there are certain tasks which are needed over and over again. For example, almost every program uses input validation to prevent a user entering data which cannot be acceptable and which might cause the program to fail. Rather than every programmer having to write the code for an input validation routine, this module of code can be taken from a module library to be re-used or adapted. There are many other standard algorithms, including: Finding the maximum value Finding the minimum value Linear Search Counting Occurrences Task 17: Highest Mark find maximum algorithm Task 17: Finding the Maximum Value Problem specification Design and write a program that generates 5 random marks between 1 and 100 and stores them in an array. The marks are displayed then the highest mark is displayed. FORM DESIGN PROPERTIES HEADING Label: Name: lblheading Text: Findinf the Maximum EXIT Button: Name: cmdexit Text: EXIT START button: Name: cmdstart Text: START LISTBOX1: Name: listbox1 Higher Computing Science 36

37 TOPIC 7 STANDARD ALGORITHMS DESIGN MAIN STEPS 1. initialise variables() in/out: max, marks_array 2. fill array with data () in/out: marks_array 3. display the array in: marks_array 4. find the maximum value in: marks_array in/out: max 5. display max in: max DESIGN REFINEMENTS Refine step 1 initialise variables() 1.1 clear contents of list box 1.2 start loop counter from 0 to set marks_array (loop counter) to End loop 1.5 Set max to 0 Refine step 2 fill array with data () in/out: max, marks_array in/out: marks_array 2.1 start loop counter from 0 to set marks_array (loop counter) to a random value between 1 and End loop Refine step 3 display the array in: marks_array 3.1 display title Here are the marks: 3.2 display a blank line 3.3 start loop counter from 0 to display marks_array (loop counter) 3.5 End loop Refine step 4 find the maximum value in: marks_array in/out: max 3.1 set max to equal the first element in the array 3.2 start loop for the rest of the array 3.3 If marks_array (loop counter) is greater than max then 3.4 set max to equal marks_array (loop counter) 3.5 End If 3.6 End loop Refine step 4 display max in: max 3.1 Display a blank line 3.2 Display The highest mark is and max Higher Computing Science 37

38 TOPIC 7 STANDARD ALGORITHMS CODE Public Class Form1 'Standard Algorithm task - Find the max Private Sub cmdstart_click(sender As Object, e As EventArgs) Handles cmdstart.click 'contains the main steps of the problem 'declare the parameters Dim marks_array (4) As Integer Dim max As Integer Randomize() initialise(max, marks_array) fill_random_marks(marks_array) display_array(marks_array) find_max(max, marks_array) display_maximum(max) Private Sub initialise(byref max, ByRef marks_array) ' this module sets an initial value to the parameters Dim index As Integer ListBox1.Items.Clear() For index = 0 To 4 marks_array(index) = 0 Next max = 0 Private Sub fill_random_marks(byref marks_array) ' this module will populate the array with random marks between 1 and 100 Dim index As Integer For index = 0 To 4 marks_array(index) = Int(Microsoft.VisualBasic.Rnd() * 100) + 1 Next Private Sub display_array(byref marks_array) 'this module will display the random marks Dim index As Integer ListBox1.Items.Add("Here are the marks: ) ListBox1.Items.Add("") For index = 0 To 4 ListBox1.Items.Add(marks_array(index)) Next Higher Computing Science 38

39 TOPIC 7 STANDARD ALGORITHMS Private Sub find_max(byref max, ByRef marks_array) ' this module will find the highest mark in the array Dim index As Integer max = marks_array(0) For index = 1 To 4 If marks_array(index) > max Then max = marks_array(index) End If Next Private Sub display_maximum(byval max) ' this module will display the highest mark ListBox1.Items.Add("") ListBox1.Items.Add("The highest marks is & max) End Class Load and run Higher Task 17 Highest mark. OUTPUT Test your program works by running it a few times. Ensure the following works correctly: The program picks up the correct value each time The program is correct when the max value is the first item in the array Higher Computing Science 39

40 TOPIC 7 STANDARD ALGORITHMS Task 18: Find the Min and Max temperature Problem specification Design, implement and test a program to do the following: The program should ask the user to enter the average temperature that occurred each day for one week. The program will display these temperatures and then display the highest and lowest temperature for the week. Example: Day 1: Day 2: Day 3: Day 4: Day 5: Day 6: Day 7: 12 degrees 10 degrees 17 degrees 6 degrees 18 degrees 9 degrees -6 degrees Highest temperature was 18 degrees Lowest temperature was -6 degrees Create a design for your Form and for your Code showing the data flow for the problem. Show this to your teacher before you implement this program. Task 19: Find the days that had the min and max temperature Problem specification Improve your last program so that it displays output like this:- Sunday: Monday: Tuesday: Wednesday: Thursday : Friday: Sunday: 12 degrees 10 degrees 17 degrees 6 degrees 18 degrees 9 degrees -6 degrees Highest temperature was 18 degrees on Thursday Lowest temperature was -6 degrees on Sunday Create a design for your Form and for your Code showing the data flow for the problem. Show this to your teacher before you implement this program. Higher Computing Science 40

41 TOPIC 7 STANDARD ALGORITHMS Task 20: Mark Counter - Count Occurrences Problem specification Design and write a program that asks the user to enter 10 marks between 0 and 100. The marks should be displayed then the user should be asked to enter a target mark that they want to count the occurrences of. The number of times that the target mark appears in the array should be displayed. FORM DESIGN PROPERTIES HEADING Label: Name: lblheading Text: Findinf the Maximum EXIT Button: Name: cmdexit Text: EXIT START button: Name: cmdstart Text: START LISTBOX1: Name: listbox1 Higher Computing Science 41

42 TOPIC 7 STANDARD ALGORITHMS DESIGN MAIN STEPS 1. initialise variables in/out: marks_array, target, counter 2. take in marks in/out: marks_array 3. target = validated number in: prompt, low, high in/out: target 4. count occurrences of target in: target, marks_array, in/out: counter 5. display results in: marks_array, target, counter DESIGN REFINEMENTS Refine step 1 initialise variables() in/out: marks_array, target, counter 1.1 start loop counter from 0 to set marks_array(loop counter) to End loop 1.4 Set counter to Set target to 0 Refine step 2 take in marks in/out: marks_array 2.1 start loop counter from 0 to marks_array(loop counter) = validated number (use get_valid_number function) 2.3 End loop Refine step 3: Function: get valid number in: prompt, low, high out: number 1. ask the user to enter a number between low and high 2. Loop while the number is less than low or greater than high 3. Display an error message to the user 4. Ask the user to re-enter the number 5. End loop 6. return number Refine step 4 count occurrences of target 4.1 start loop counter from 0 to If marks_array(loop counter) = target 4.3 add 1 to counter 4.4 End If statement 4.5 End loop Refine step 5 display results in: target, marks_array, in/out: counter in: marks_array, target, counter 5.1 Display Here are the marks 5.2 Start loop counter from 0 to Display marks_array(loop counter) 5.4 End loop 5.5 Display a blank line 5.6 Display The target being counted is and target 5.7 Display it was found and counter and times Higher Computing Science 42

43 TOPIC 7 STANDARD ALGORITHMS CODE Public Class Form1 ' Standard algorithms task - Count Occurences of a value in a list Private Sub cmdstart_click(sender As Object, e As EventArgs) Handles cmdstart.click 'declare the parameters used Dim marks_array(9) As Integer Dim target, counter As Integer 'main steps of the problem initialise(marks_array, target, counter) take_in_marks(marks_array) target = get_valid_number("what mark do you want to search for? Enter a mark between, 0, 100) count_occurences(marks_array, target, counter) display_results(marks_array, target, counter) Private Sub initialise(byref marks_array, ByRef target, ByRef counter) 'set an initial value to all parameters used in the program Dim index As Integer For index = 0 To 9 marks_array(index) = 0 Next counter = 0 target = 0 Private Sub take_in_marks(byref marks_array) 'populate the array with valid marks from the user Dim index As Integer For index = 0 To 9 marks_array(index) = get_valid_number("please enter the mark for pupil " & index + 1, 1, 100) Next Function get_valid_number(byval prompt, byval low, byval high) As Integer 'function used to validate a number between 2 boundaries Dim number as integer number = Val(InputBox(prompt & low & and & high)) Do While number < low Or number > high MsgBox("That number is invalid. Please try again") number = Val(InputBox(prompt & low & and & high)) Loop Return number End Function Higher Computing Science 43

44 TOPIC 7 STANDARD ALGORITHMS Private Sub count_occurences(byref marks_array, ByVal target, ByRef counter) 'count how many times the target appears in the list Dim index As Integer For index = 0 To 9 If marks_array(index) = target Then counter = counter + 1 End If Next Private Sub display_results(byref marks_array, ByVal target, ByVal counter) 'display the marks entered, the targer being searched for and the number of occurrences Dim pupil As Integer End Class ListBox1.Items.Add("Here are the marks:") For index = 0 To 9 ListBox1.Items.Add(marks_array(index)) Next ListBox1.Items.Add("") ListBox1.Items.Add("The target being counted is :" & target) ListBox1.Items.Add("It was found " & counter & " times") Load and run Higher Task 20 Count Occurrences. OUTPUT Higher Computing Science 44

45 TOPIC 7 STANDARD ALGORITHMS Test your program with the following test data: Test Type of Test 1 Normal 2 Normal 3 Extreme 4 Extreme 5 Exceptional 6 Exceptional Test data 15,45,47,45,89,62,36,34,45,25 TARGET = 45 15,95,47,45,89,62,36,34,55,25 TARGET = 45 45,45,45,45,45,45,45,45,45,45 TARGET = 45 0,0,1,1,99,99,100,100,0,100 TARGET = 45 Enter mark below 0 and over 100 Enter target below 0 and over 100 Expected Result Target of 45 appears 3 times Target of 45 appears 1 times Target of 45 appears 10 times Target of 45 appears 0 times Error message for mark Error message for target Task 21: Count the number of days that were a target temperature Count Occurrences Problem specification Improve your temperature program so that it also asks the user to enter a target temperature and displays output like this:- Sunday: Monday: Tuesday: Wednesday: Thursday : Friday: Sunday: 12 degrees 10 degrees 17 degrees 10 degrees 18 degrees 9 degrees -6 degrees Highest temperature was 18 degrees on Thursday Lowest temperature was -6 degrees on Sunday The number of days that it was 10 degrees was 2. Create a design for your Form and for your Code showing the data flow for the problem. Show this to your teacher before you implement this program. Higher Computing Science 45

46 TOPIC 7 STANDARD ALGORITHMS Task 22: Who got a target mark - Linear search Problem specification Design and write a program that fills an array with 10 marks then asks the user to enter a target mark. The program should then display the number of each pupil who got the target mark. FORM DESIGN PROPERTIES Property Property HEADING Label: Name: lblheading Text: Linear Search EXIT Button: Name: cmdexit Text: EXIT START button: Name: cmdstart Text: START LISTBOX1: Name: listbox1 Higher Computing Science 46

47 DESIGN MAIN STEPS TOPIC 7 STANDARD ALGORITHMS 1. initialise variables() in/out: target 2. display marks () in: marks_array 3. target = validated number in: prompt, low, high out: target 4. linear search in: marks_array, target DESIGN REFINEMENTS Refine step 1 initialise variables() in/out: target 1.1 clear the contents of the listbox 1.2 Set target to 0 Refine step 2 display marks in: marks_array 2.1 Display Here are the marks 2.2 Display a blank line 2.3 start loop counter from 0 to display the pupils mark 2.5 end loop Refine step 3: Function: get valid number in: prompt, low, high out: number 1. ask the user to enter a number between low and high 2. Loop while the number is less than low or greater than high 3. Display an error message to the user 4. Ask the user to re-enter the number 5. End loop 6. return number Refine step 4 linear search in: marks_array, target 4.1 set flag to false 4.2 Display a blank line 4.3 Start loop from 0 to If the value in marks_array(loop counter) = target 4.5 Display the position of this target loop counter 4.6 Set flag to true 4.7 End if statement 4.8 End loop 4.9 If flag is false display Target not found in list Higher Computing Science 47

48 TOPIC 7 STANDARD ALGORITHMS CODE Public Class Form1 ' Standard Algorithms - Linear Search Private Sub cmdstart_click(sender As Object, e As EventArgs) Handles cmdstart.click ' declare parameters and initialise array with values Dim marks_array() As Integer = {10, 15, 14, 13, 9, 14, 12, 18, 9, 10} Dim target As Integer initialise(target) display_marks(marks_array) target = get_valid_number("what mark do you want to search for? Enter a number between ", 0, 20)) linear_search(marks_array, target) Private Sub initialise(byref target) 'this module will set an initial value for the target ListBox1.Items.Clear() target = 0 Private Sub display_marks(marks_array) 'this module will display the values stored in the array Dim index As Integer ListBox1.Items.Add("Here are the marks out of 20:") ListBox1.Items.Add("") For index = 0 To 9 ListBox1.Items.Add("Pupil " & index + 1 & ": " & marks_array(index)) Next Private Sub linear_search(byref marks_array, ByVal target) 'this module will search the array for occurences of the target value and report their position Dim index As Integer Dim found As Boolean found = False ListBox1.Items.Add("") For index = 0 To 9 If marks_array(index) = target Then ListBox1.Items.Add("The target of " & target & " was found for pupil " & index + 1) found = True End If Next If found = False Then ListBox1.Items.Add("Target " & target & " not found in the list") Function get_valid_number(byval prompt, byval low, byval high) As Integer 'function used to validate a number between 2 boundaries Dim number as integer number = Val(InputBox(prompt & low & and & high)) Do While number < low Or number > high MsgBox("That number is invalid. Please try again") number = Val(InputBox(prompt & low & and & high)) Loop Return number End Function End Class Higher Computing Science 48

49 TOPIC 7 STANDARD ALGORITHMS Load and run Higher Task 22 Linear search. OUTPUT Your output should look like this: Adapt your program to work with the following test data: Test Type of Test 1 Normal 2 Normal 3 Extreme 4 Extreme 5 Exceptional 6 Exceptional Test data 11, 12, 10, 12, 10, 19, 18, 20, 12, 8 TARGET = 12 11, 12, 10, 12, 10, 19, 18, 20, 12, 8 TARGET = 10 11,11,11,11,11,11,11,11,11,11 TARGET = 20 0,0,1,1,9,9,10,20,10,18 TARGET = 0 0,0,1,1,9,9,10,20,10,18 TARGET = -3 0,0,1,1,9,9,10,20,10,18 TARGET = 21 Expected Result Target appears for pupil 2 Target appears for pupil 4 Target appears for pupil 9 Target appears for pupil 3 Target appears for pupil 5 Target 20 not on the list Target appears for pupil 1 Target appears for pupil 2 Error message for target Error message for target Higher Computing Science 49

50 TOPIC 7 STANDARD ALGORITHMS Task 23: Search for the days that were a target temperature Problem specification Improve your temperature program so that it also displays the days that matched the target temperature. It should display output like this:- Sunday: Monday: Tuesday: Wednesday: Thursday : Friday: Sunday: 12 degrees 10 degrees 17 degrees 10 degrees 18 degrees 9 degrees -6 degrees Highest temperature was 18 degrees on Thursday Lowest temperature was -6 degrees on Sunday The number of days that it was 10 degrees was 2. It was 10 degrees on Monday. It was 10 degrees on Wednesday. Higher Computing Science 50

51 TOPIC 8 READING FROM A SEQUENTIAL FILE Topic 8 Reading from a sequential file Task 24: Read hotel data from a Comma Separated Value file and store it in arrays Problem specification Design and create a program that reads data from a file and stores it in arrays. The output should look like this:- The Comma Separated Value file looks like this:- Higher Computing Science 51

52 TOPIC 8 READING FROM A SEQUENTIAL FILE DESIGN MAIN STEPS 1. initialize in/out: hotelname, hotelrating, hotelcity, hotelpricepernight, hotelmealsincluded, countofhotels 2. read_file_into_records() in/out: hotelname, hotelrating, hotelcity, hotelpricepernight, hotelmealsincluded, countofhotels 3. display_records() in: hotelname, hotelrating, hotelcity, hotelpricepernight, hotelmealsincluded, countofhotels DESIGN REFINEMENTS Refine step 1 initialise in/out: hotelname, hotelrating, hotelcity, hotelpricepernight, hotelmealsincluded, countofhotels 1.1 start loop counter from 1 to set hotelname(loop counter) to 1.3 set hotelrating(loop counter) to set hotelcity(loop counter) to 1.5 set hotelpricepernight(loop counter) to set hotelmealsincluded(loop counter) to 1.7 end loop 1.8 set countofhotels to 0 Refine step 2 read_file_into_arrays() in/out: hotelname, hotelrating, hotelcity, hotelpricepernight, hotelmealsincluded, countofhotels 2.1 Using myreader to Open a file to read from it 2.2 set countofhotels to loop while not at the end of the data 2.4 try 2.5 set currentrow to a line in the file 2.6 add 1 to countofhotels 2.7 set allhotels(countofhotels).hotelname field to string 0 in the current line 2.8 set allhotels(countofhotels). hotelrating field to value 1 in the current line 2.9 set allhotels(countofhotels). hotelcity field to string 2 in the current line 2.10 set allhotels(countofhotels). hotelpricepernight field to value 3 in the current line 2.11 set allhotels(countofhotels). hotelmealsincluded field to string 4 in the current line 2.12 Catch file error 2.13 display error message 2.1 end try 2.1 end loop 2.1 End Using 2 Higher Computing Science 52

53 TOPIC 8 READING FROM A SEQUENTIAL FILE Refine step 3 display_records() in/out: hotelname, hotelrating, hotelcity, hotelpricepernight, hotelmealsincluded, countofhotels 3.1 start loop counter from 1 to countofhotels 3.2 send allhotels(loop counter).hotelname to display 3.3 send allhotels(loop counter).hotelrating to display 3.4 send allhotels(loop counter).hotelcity to display 3.5 send allhotels(loop counter).hotelpricepernight to display 3.6 send allhotels(loop counter).hotelmealsincluded to display 3.7 end loop Public Class Form1 Private Sub cmdstart_click(sender As Object, e As EventArgs) Handles cmdstart.click Dim hotelname(5) As String Dim hotelrating(5) As Integer Dim hotelcity(5) As String Dim hotelpricepernight(5) As Single Dim hotelmealsincluded(5) As String Dim countofhotels As Integer initialise(hotelname, hotelrating, hotelcity, hotelpricepernight, hotelmealsincluded, countofhotels) read_file_into_arrays(hotelname, hotelrating, hotelcity, hotelpricepernight, hotelmealsincluded, countofhotels) display_arrays(hotelname, hotelrating, hotelcity, hotelpricepernight, hotelmealsincluded, countofhotels) Private Sub initialise(byref hotelname, ByRef hotelrating, ByRef hotelcity, ByRef hotelpricepernight, ByRef hotelmealsincluded, ByRef countofhotels) Dim index As Integer For index = 1 To 5 hotelname(index) = "" hotelrating(index) = 0 hotelcity(index) = "" hotelpricepernight(index) = 0 hotelmealsincluded(index) = "" Next countofhotels = Higher Computing Science 53

54 TOPIC 8 READING FROM A SEQUENTIAL FILE Private Sub read_file_into_arrays(byref hotelname, ByRef hotelrating, ByRef hotelcity, ByRef hotelpricepernight, ByRef hotelmealsincluded, ByRef countofhotels) 'reads a comma separated value file into 5 arrays Using MyReader As New Microsoft.VisualBasic.FileIO.TextFieldParser("N:\Visual Studio 2012\Hotel Info.csv") MyReader.TextFieldType = FileIO.FieldType.Delimited MyReader.SetDelimiters(",") Dim currentrow As String() ' Dim numberoffields As Integer While Not MyReader.EndOfData Try currentrow = MyReader.ReadFields() 'numberoffields = currentrow.getupperbound(0) ' MsgBox(numberOfFields) countofhotels = countofhotels + 1 hotelname(countofhotels) = currentrow(0).tostring hotelrating(countofhotels) = Val(currentRow(1).ToString) hotelcity(countofhotels) = currentrow(2).tostring hotelpricepernight(countofhotels) = Val(currentRow(3).ToString) hotelmealsincluded(countofhotels) = currentrow(4).tostring Catch ex As Microsoft.VisualBasic. FileIO.MalformedLineException MsgBox("Line " & ex.message & "is not valid and will be skipped.") End Try End While End Using Private Sub display_arrays(byref hotelname, ByRef hotelrating, ByRef hotelcity, ByRef hotelpricepernight, ByRef hotelmealsincluded, ByVal countofhotels) For index = 1 To countofhotels ListBox1.Items.Add(hotelName(index)) ListBox2.Items.Add(hotelRating(index)) ListBox3.Items.Add(hotelCity(index)) ListBox4.Items.Add(hotelPricePerNight(index)) ListBox5.Items.Add(hotelMealsIncluded(index)) Next Private Sub cmdexit_click(sender As Object, e As EventArgs) Handles cmdexit.click End End Class Copy the CSV file called Hotel Info into your Visual Studio 2012 folder. Load and run Higher Task 24 Read a hotel file into arrays. Higher Computing Science 54

55 TOPIC 8 READING FROM A SEQUENTIAL FILE Task 25: Notice the difference here actual and formal parameter can have different names Load and run Higher Task 25 Read a hotel file into arrays using standard modules. Public Class Form1 Private Sub cmdstart_click(sender As Object, e As EventArgs) Handles cmdstart.click 'This module contains the main program Dim hotelname(5) As String Dim hotelrating(5) As Integer Dim hotelcity(5) As String Dim hotelpricepernight(5) As Single Dim hotelmealsincluded(5) As String Dim countofhotels As Integer initialise(hotelname, hotelrating, hotelcity, hotelpricepernight, hotelmealsincluded, countofhotels) read_file_into_arrays(hotelname, hotelrating, hotelcity, hotelpricepernight, hotelmealsincluded, countofhotels) display_arrays(hotelname, hotelrating, hotelcity, hotelpricepernight, hotelmealsincluded, countofhotels) Private Sub initialise(byref hotelname, ByRef hotelrating, ByRef hotelcity, ByRef hotelpricepernight, ByRef hotelmealsincluded, ByRef countofhotels) 'This module will initialise the records so that the string fields are set to "" and the numeric fields, countofhotels and are set to 0 Dim index As Integer For index = 1 To 5 hotelname(index) = "" hotelrating(index) = 0 hotelcity(index) = "" hotelpricepernight(index) = 0 hotelmealsincluded(index) = "" Next countofhotels = Higher Computing Science 55

56 TOPIC 8 READING FROM A SEQUENTIAL FILE Private Sub read_file_into_arrays(byref array1, ByRef array2, ByRef array3, ByRef array4, ByRef array5, ByRef count) 'this module reads a comma separated value file into some arrays Using MyReader As New Microsoft.VisualBasic.FileIO.TextFieldParser("N:\Visual Studio 2012\Hotel Info.csv") MyReader.TextFieldType = FileIO.FieldType.Delimited MyReader.SetDelimiters(",") Dim currentrow As String() While Not MyReader.EndOfData Try currentrow = MyReader.ReadFields() 'reads a line of the csv and stores it in the string variable called currentrow count = count + 1 'keeps track of which line of the file was read a value a value puts the values that are separated by the commas into the arrays array1(count) = currentrow(0).tostring array2(count) = Val(currentRow(1).ToString) 'val converts a string to array3(count) = currentrow(2).tostring array4(count) = Val(currentRow(3).ToString) 'val converts a string to array5(count) = currentrow(4).tostring End While End Using Catch ex As Microsoft.VisualBasic. FileIO.MalformedLineException MsgBox("Line " & ex.message & "is not valid and will be skipped.") End Try Private Sub display_arrays(byref array1, ByRef array2, ByRef array3, ByRef array4, ByRef array5, ByVal count) 'this module will display the contents of some arrays Dim index As Integer For index = 1 To count ListBox1.Items.Add(array1(index)) ListBox2.Items.Add(array2(index)) ListBox3.Items.Add(array3(index)) ListBox4.Items.Add(array4(index)) ListBox5.Items.Add(array5(index)) Next Private Sub cmdexit_click(sender As Object, e As EventArgs) Handles cmdexit.click End End Class Higher Computing Science 56

57 TOPIC 8 READING FROM A SEQUENTIAL FILE Task 26: Improve the hotel data program so that it uses the Find max and Linear search procedures Problem specification Improve the hotel data program that reads data from a file and stores it in arrays so that it also displays the highest rating and the hotels that had that rating. To test it you should change your Comma Separated Value file so that the Paisley Palm hotel has a rating of 5. The output should look like this:- Task 27: Read pupil data from a Comma Separated Value file and store it in arrays Problem specification Design and create a program that reads data from a file and stores it in arrays. The data should include Forename, Surname, Register Class, Date of Birth. You will need to create a Comma Separated Value file like this:- John, Smith,5L,18/1/1998 Susan, Brown,5M,20/3/1998 Katie,Jones,5L,12/4/1998 Kara,Green,5M,2/1/1998 Higher Computing Science 57

58 TOPIC 9 USING RECORDS Topic 9 Using records Task 28: Enter hotel data and store it in records Problem specification Design and create a program that allows the user to enter data about hotels and stores it in records. It should display output like this:- The data will be stored in records in an array of records like this:- Array hotelname hotelrating hotelcity hotelpricepernight hotelmealsincluded Index 0 1 Glasgow 5 Glasgow Breakfast Caledonian 2 Aberdeen Arms 3 Aberdeen Breakfast 3 Paisley Palm 4 Paisley None 4 Premier Inn 2 Glasgow None 5 Premier Inn 2 Carlisle All meals Higher Computing Science 58

59 TOPIC 9 USING RECORDS DESIGN MAIN STEPS 1. initialise variables() in/out: allhotels, countofhotels 2. store_data_in_records() in/out: allhotels, countofhotels 3. display_records() in: allhotels, countofhotels DESIGN REFINEMENTS Refine step 2 initialise variables() in/out: allhotels, countofhotels 1.1 set countofhotels to start loop counter from 1 to countofhotels 1.3 set allhotels(loop counter).hotelname to 1.4 set allhotels(loop counter).hotelrating to 1.5 set allhotels(loop counter).hotelcity to 1.6 set allhotels(loop counter).hotelpricepernight to 1.7 set allhotels(loop counter).hotelmealsincluded to 1.8 end loop Refine step 2 store_data_in_records() in/out: allhotels, countofhotels 2.1 start loop counter from to countofhotels 2.2 receive set allhotels(loop counter).hotelname from keyboard 2.3 receive set allhotels(loop counter).hotelrating from keyboard 2.4 receive set allhotels(loop counter).hotelcity from keyboard 2.5 receive set allhotels(loop counter).hotelpricepernight from keyboard 2.6 receive set allhotels(loop counter).hotelmealsincluded from keyboard 2.7 end loop Refine step 3: display_records() in: allhotels, countofhotels 3.1 start loop counter from to countofhotels 3.2 send allhotels(loop counter).hotelname to display 3.3 send allhotels(loop counter).hotelrating to display 3.4 send allhotels(loop counter).hotelcity to display 3.5 send allhotels(loop counter).hotelpricepernight to display 3.6 send allhotels(loop counter).hotelmealsincluded to display 3.7 end loop Higher Computing Science 59

60 TOPIC 9 USING RECORDS Public Class Form1 Structure hotelrecord 'Declare the strucre of a record Dim hotelname As String Dim hotelrating As Integer Dim hotelcity As String Dim hotelpricepernight As Single Dim hotelmealsincluded As String End Structure Private Sub cmdstart_click(sender As Object, e As EventArgs) Handles cmdstart.click ' Main program Dim countofhotels As Integer Dim allhotels(5) As hotelrecord initialise(allhotels, countofhotels) store_data_in_records(allhotels, countofhotels) display_records(allhotels, countofhotels) Private Sub initialise(byref allhotels() As hotelrecord, ByRef countofhotels As Integer) 'This module gives the records and countofhotels initial values Dim index As Integer countofhotels = 5 'Set the number of hotels that are to be stored For index = 1 To countofhotels allhotels(index).hotelname = "" allhotels(index).hotelrating = 0 allhotels(index).hotelcity = "" allhotels(index).hotelpricepernight = 0 allhotels(index).hotelmealsincluded = "" Next Private Sub store_data_in_records(byref allhotels() As hotelrecord, ByVal countofhotels As Integer) 'This module invites the user to enter data that is stored in an array of records Dim index As Integer For index = 1 To countofhotels allhotels(index).hotelname = InputBox("Enter the name of hotel " & index) allhotels(index).hotelrating = InputBox("Enter the rating of hotel " & index) allhotels(index).hotelcity = InputBox("Enter the city of hotel " & index) allhotels(index).hotelpricepernight = InputBox("Enter the price per night of hotel " & index) allhotels(index).hotelmealsincluded = InputBox("Enter the meals included of hotel " & index) Next Higher Computing Science 60

61 TOPIC 9 USING RECORDS Private Sub display_records(byref allhotels() As hotelrecord, ByVal countofhotels As Integer) 'This module displays the data that is stored in an array of records Dim index As Integer For index = 1 To countofhotels ListBox1.Items.Add(allHotels(index).hotelName) ListBox2.Items.Add(allHotels(index).hotelRating) ListBox3.Items.Add(allHotels(index).hotelCity) ListBox4.Items.Add(allHotels(index).hotelPricePerNight) ListBox5.Items.Add(allHotels(index).hotelMealsIncluded) Next Private Sub cmdexit_click(sender As Object, e As EventArgs) Handles cmdexit.click End End Class Load and run the program called Higher Task 28 Enter hotel data into records. Try changing it store a different number of records. Higher Computing Science 61

62 TOPIC 9 USING RECORDS Task 29: Read hotel data from a Comma Separated Value file and store it in records Problem specification Improve the hotel records program so that the data is read from a file instead of the user entering it. The output should still looks like this:- The Comma Separated Value file looks like this:- Higher Computing Science 62