MIS 216 SPRING 2018 PROJECT 4

Transcription

1 MIS 216 SPRING 2018 PROJECT 4 Subs / Functions Arrays / Classes 1. Start a new project a. Create a folder on your desktop name it yourinitialsproject3 as in tnjproject3. b. FILE NEW PROJECT c. Change the Path to Desktop d. Change the name to yourintialsproject4 e. STOP at this point, and reduce the Visual Studio Window and look in the folder you created, do you see Form1.vb in one of the sub folders? If not delete the folder, close Visual Studio and start again. f. In the same folder as your form1.vb file, add a new folder - images 2. Your task will be build 2 forms in this project to reflect your ability to build user friendly forms that will calculate various totals for items selected or desired. 3. This project will be similar to Projects 3 in that one form will have multiple buttons to accomplish multiple samples of a new concept, however we will add an additional form to provide additional learning. A major goal of this project is to learn to repeat

2 code, we will also add comments under each button or subroutine to tell the user what the button will do. On your form shown on the previous page: a. Add a lblmessage to the top center of the form, set the borders to single and the Min Size to 200,20. Also set the fore color to something other than black b. Add 5 labels across the screen as shown c. Add 5 text boxes, name them txtinput1, txtinput2, etc. d. Add 5 buttons, name them btn1, btn2, etc., change the text property as shown e. Add two more buttons to the form, one to take you to form 2 (described later) and one to End the application. Place the proper code under the END button. 4. For all buttons, place any error messages or the valid results in the lblmessage 5. Create your first function that will return TRUE if the value entered is a number, or FALSE if it is not. Go to your code window and type the following (it should be placed immediately before the END CLASS Private Function checknumber(byval strin As String) As Boolean If Not IsNumeric(strIn) Then Return False Else Return True End If End Function We will use this function many times over the next few buttons 6. btn1 Will check for # s entered. Change the text property for the button as shown in the figure, add a comment as the first line of code under the submit button: 'Demonstrate the use of a function to test if a value entered is a number a. Now Call the function and if it returns false, display an error message, here is the first IF statement. Note we will use a Boolean to track if we have any errors Dim isok as Boolean = true If checknumber(me.txtinput1.text) = False Then Me.lblMessage.Text = "Input 1 must be a number" isok = false End If b. Repeat for txtinput2 and txtinput3 (call the function 2 more times) c. If you get to the end without any errors, place All is OK in lblmessage If isok = true then lblmessage.text = All OK End if d. Test by entering letters in txt1 to 3 and see if you get errors, then place # s in txt1 to 3 and see if you get All is OK.

3 7. Btn2 will check for # s and then check to see if the values entered are between 0 and 150. Change the text property of the button as shown, and add a comment in the first line of code in the SUB to tell the reader what the sub accomplishes. a. Copy all the code from btn1 under this button as you want to check for numbers before you can check if they are between 0 and 150. b. Now create three Single Variables to accept input from the text boxes and convert to single (sngone, sngtwo, sngthree) c. Create a new function (before the END CLASS) as started below: Private Function checkrange(byval numin As Integer) As Boolean write code here to return false if the numin is below zero or numin > 150 else return true End Function d. Back in your subroutine under btn2 (after the dim statements) - call the new function created as in: If checkrange(intone) = False Then Me.lblMessage.Text = "Input 1 must be between 0 and 150" isok = false End If e. Call the function 2 more times for the other 2 input boxes f. If you get to the end without any errors, place All are between 0 and 150 in lblmessage g. Test! 8. Btn3 Is a variation on btn2, but will let the user enter the lower and upper limits for validation to determine if a number is in the range into txtinput2 and txtinput3. So a user could enter 25 in txtiinput1, 0 in txtinput2 and 50 in txtinput3 and you would say YES it is in the range. Thus you will create a function that will not only pass the value entered in txtinput1, but also the upper and lower limits. Change the text on the button and add a comment. a. Create a new function, name it checkinputrange, it will have 3 values passed to as in: Public Function checkinputrange(byval numin As single, ByVal lowerlimit As single, ByVal upperlimit As single) As Boolean write code here to return false if the numin is below the lowerlimit or above the upper limit, else return true

4 End Function b. Repeat the steps from btn2 to check for numbers c. Repeat the steps from btn2 to convert the strings in the text boxes to Single Values d. Now call the new function as in: If checkinputrange(it will want 3 values here from your single variables) = false.. lblmessage.text = Input 1 is not between & show the upper and lower limits else lblmessage.text = Input 1 is between & show the upper and lower limits end if 9. Btn4 will calculate the GPA for 5 grades entered, Assume they are full letter grades (not + or -) Change the text on the button and add a comment. e. Create a new function Private Function getonecoursegpa(byval gradein As String) As Single i. f. In this function place a Select Case statement that will return ii. 12 if an A iii. 9 if a B iv. 6 if a C v. 3 if a D vi. Else 0 g. Under btn4, declare a variable to store the total points earned (sngpoints) h. Call your new function 5 times and add the results to sngpoints, here is the first call: sngpoints = sngpoints + getonecoursegpa(me.txtinput1.txt) i. Divide sngpoints by 15 and show the answer in the lblmessage formatted to 2 decimal places. 10. Btn5 will calculate the GPA for 5 grades entered, Assume there might be + and grades entered. Change Text and add a comment. j. Create a new function (getonecoursegpaplusminus) k. Copy your Select Case from your previous function, but add in new cases for: vii. A-, 11; B+, 10; B-, 8; C+ 7; C- 5, D+, 4; D- 2 l. Call this new function and show the results formatted to 2 decimal places. 11. Add a new form to your project m. Right click on the name of your project in the Solution Explorer Window n. Then click ADD, and then NEW ITEM o. Then Windows Form, change the name to be frmarrays p. Save

5 12. Change the code on the original form under the Go To Form 2 to be: q. frmarrays.show 13. Build the form as shown in the next figure, names should be lsttemps, btn1 to 4, lblmessage 14. Into lsttemps, place the values shown in the previous figure, these are the actual highs for February, 2014 for Wilmington. Check your values. 15. Now we will build an array that we can use in ALL our buttons. On your code page, place this definition of the array, on the line after the Public Class line: Dim temps(27) As Integer 16. Create a subroutine (name it: buildarray), the subroutine should: a. Dim an intctr as an integer set to zero b. Build a FOR EACH statement to go through the list box and move the values to the array: For Each intitem As Integer In Me.lstTemps.Items temps(intctr) = intitem intctr += 1

6 Next 17. btn 1 you will calculate the average high temperature for February, change the text of the button and add a comment. c. First call the function to load the array as in : buildarray() d. Write a function that will average the temperature based on the number of entries in the array (so it could be used for any month), think of the use of.count e. Display the average in lblmessage to 2 decimals, with a comment like: viii. The average high temperature for February was: & ##.## 18. Btn2 will ask the user to enter a date and you will report back the high temperature for that date, change the text and add a comment. Here are the first three lines of this button: buildarray() Dim intdatedesired As Integer = 0 intdatedesired = InputBox("Enter date for the high temperature ") lblmessage should now be a clear comment as in: ix. On February xxx the high was xxx 19. Btn3 will report the highest temperature and date for the month. a. This code will help you get started: buildarray() then think of using the max function b. You will need a FOR EACH statement here and loop through the ARRAY to determine the high. c. Will discuss this in class, so if you miss get notes from a student d. lblmessage should result in: The highest temperature in February was xxx on xxx 20. Btn4 is the reverse of btn3 and should report the low temperature and date Test your work Zip your folder Load your folder to entropy for Project 4 (make sure the size is not less than 10K when you upload it), Click the VERIFY Uploads link in Entropy to see the size.