SNS COLLEGE OF ENGINEERING

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1 SNS COLLEGE OF ENGINEERING DEPARTMENT OF CSE Presented By Thillaiarasu.N

2 SCRAMBLE 2

3 Solution 3

4 What is Pseudocode? 4 Consists of: Short Readable Formally styled English language Used for: Explaining the algorithm Does not include: variable declaration

5 Why Pseudocode? 5 Detailed algorithm before developing a program is very time consuming It focuses on only logic of program It is not written using specific syntax Written by using combination of Generic syntax and normal English language

6 Rules for Pseudocode 6 1.Write only one statement per line 2.Capitalize initial keyword 3.Indent to show hierarchy 4.End multiline structures 5.Keep statements language independent

7 Terms 7 Input data INPUT, GET, READ Calculation Output COMPUTE, CALCULATE OUTPUT, PRINT, DISPLAY Incrementing INCREMENT Addition, Subtraction, Initialization ADD, SUBTRACT, INITIALIZE

8 Guidelines 8 Steps should be understandable Capitalize the keyword. Indent to show hierarchy. End multiple line structure etc,.

9 One Statement Per Line 9 Each statement in pseudocode * should express just one action for the computer. * If the task list is properly drawn -then in most cases each task will correspond to one line of pseudocode. Task List Read name, hours worked, rate of pay Perform calculations gross = hours worked * rate of pay Write name, hours worked, gross Pseudocode READ name, hoursworked, payrate gross = hoursworked * payrate WRITE name, hoursworked, gross

10 Capitalize Initial Keyword 10 Keywords: READ WRITE IF ELSE ENDIF WHILE ENDWHILE Pseudocode READ name, hoursworked, payrate gross = hoursworked * payrate WRITE name, hoursworked, gross

11 Indent to Show Hierarchy 11 Each design structure uses a particular indentation pattern READ name, grosspay, taxes IF taxes > 0 net = grosspay taxes ELSE net = grosspay ENDIF WRITE name, net

12 Control Structures 12 Sequence Selection Iteration : : Step 1 Step 2 Step 3 IF(condition) THEN statement 1 ELSE statement 2 ENDIF IF(condition) THEN statement 1 ENDIF CASE expression of Condition1: statement 1 Condition2: statement 2 WHILE (Condition) statement 1 statement 2 : : END Do statement 1 statement 2 : : WHILE (Condition)

13 End Multiline Structures 13 READ name, grosspay, taxes IF taxes > 0 ELSE ENDIF net = grosspay taxes net = grosspay WRITE name, net ENDIF is in line with the IF. Similarly, WHILE/ENDWHILE etc

14 Puzzle 14

15 Animation 15

16 Selection Structure 16 yes amount < 100 no interestrate =.06 interestrate =.10 Pseudocode IF amount < 100 interestrate =.06 ELSE Interest Rate =.10 ENDIF

17 Looping Structure 17 Flowchart: More confusing things is to separate selection from looping. So each structure use the diamond as their control symbol. Pseudocode: we avoid this by using specific keywords to designate looping WHILE/ENDWHILE REPEAT/UNTIL

18 Pros 18 Flowchart Advantages: Standardized Visual Pseudocode Advantages Easily modified Implements structured concepts Done easily on Word Processor Works well for large program

19 Cons 19 Flowchart Pseudocode Disadvantages: Hard to modify Structured design elements not implemented Special software required Disadvantages: Not visual No accepted standard, varies from company to company

20 Access of Data 20 The READ statement tells the computer to get a value from an input device and store it in a memory location. How to deal with memory locations? Memory locations are identified by their addresses, we give them names (field names / variable names) using words descriptive to us such as ctr as opposed to a location addresses such as

21 Rules for Variable Names 21 Begin with lowercase letter Contain no spaces Additional words begin with capital Unique names within code Consistent use of names

22 Working with Fields 22 Calculations Selection + add - subtract * multiply / divide ** or ^ exponentiation ( ) grouping > greater than < less than = equal to >= greater than or equal to <= less than or equal to <> not equal to

23 23

24 24 To add 2 numbers & display result

25 25 To Compute Average of 4 numbers

26 Celsius to Fahrenheit 26

27 27 Swapping of 2 nos without using another variable

28 Selection 28

29 Greatest among 2 nos 29

30 30 Determine student final grade & indicate passed/failed

31 Positive or Negative 31

32 Odd or even 32

33 33

34 Factorial 34

35 Fibonacci Series 35 ENDWHILE

36 36 Sum of odd numbers between 1 to n

37 37

SNS COLLEGE OF ENGINEERING,

SNS COLLEGE OF ENGINEERING, COIMBATORE Department of Computer Science and Engineering QUESTION BANK(PART A) GE8151 - PROBLEM SOLVING AND PYTHON PROGRAMMING TWO MARKS UNIT-I 1. What is computer? Computers