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# Sem1 plt xp_02

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### Sem1 plt xp_02

1. 1. Representing the Logic of Programs with Conditions Objectives In this lesson, you will learn about: Data and data types Using operators Representing decisions in a flowchart ©NIIT PLT/Lesson 2/Slide 1 of 33
2. 2. Representing the Logic of Programs with Conditions Variables and Constants Flowchart to display the sum of two numbers Start Accept the First Number Accept the Second Number Add the two Numbers and Store the Result Display the Result Stop ©NIIT PLT/Lesson 2/Slide 2 of 33
3. 3. Representing the Logic of Programs with Conditions Variables and Constants (Contd.) The internal memory consists of different locations in which data is stored A computer needs to identify the memory locations to be able to retrieve values from or store values in them The value of a variable changes each time the set of instructions is executed The values stored in the variables are known as constants ©NIIT PLT/Lesson 2/Slide 3 of 33
4. 4. Representing the Logic of Programs with Conditions Variables and Constants (Contd.) Constants 10 15 25 nNum1 nNum2 nSum Variables ©NIIT PLT/Lesson 2/Slide 4 of 33
5. 5. Representing the Logic of Programs with Conditions Variables and Constants (Contd.) Flowchart to display the sum of two numbers using variables. Start Accept nNum1 Accept nNum2 nSum = nNum1 + nNum2 Display nSum Stop ©NIIT PLT/Lesson 2/Slide 5 of 33
6. 6. Representing the Logic of Programs with Conditions Just a Minute… Identify the variable and constant data in the following situation: Each day, the courier service delivers some letters. The number of letters is different each day. Regardless of the number of letters delivered by the courier service, they are paid a carrying charge of \$5. Variable: Constant: ©NIIT PLT/Lesson 2/Slide 6 of 33
7. 7. Representing the Logic of Programs with Conditions Just a Minute… Identify the variables and constants from the list given below: a) Age b) Address c) 21 d) “10, Kingsway Camp” e) “Henri” f) Name g) “185” ©NIIT PLT/Lesson 2/Slide 7 of 33
8. 8. Representing the Logic of Programs with Conditions Data Types Numeric Numeric variables can contain only numbers These variables can be used in arithmetic operations Character Character variables can contain any combination of letters, numbers, and special characters These variables cannot be used for calculation ©NIIT PLT/Lesson 2/Slide 8 of 33
9. 9. Representing the Logic of Programs with Conditions Data Types Declaring Variables Start numeric nNum1, nNum2, nSum Accept nNum1 Accept nNum2 nSum = nNum1 + nNum2 Display nSum Stop ©NIIT PLT/Lesson 2/Slide 9 of 33
10. 10. Representing the Logic of Programs with Conditions Data Types Variable Naming Conventions ® Thefirst letter of the variable may indicate the data type used ® Thevariable name should clearly describe its purpose ® In case of multiple words, the first letter of each word could be capitalized for better readability ©NIIT PLT/Lesson 2/Slide 10 of 33
11. 11. Representing the Logic of Programs with Conditions Using Operators Operators are tools for some predefined operations The operators that are used in flowcharts are: Arithmetic operators Relational operators Logical operators ©NIIT PLT/Lesson 2/Slide 11 of 33
12. 12. Representing the Logic of Programs with Conditions Using Operators Arithmetic operators Arithmetic operators are used to perform arithmetic calculations The symbols that represent arithmetic operations are called arithmetic operators (*, /, +, -, %) Relational operators Relational operators are used to test the relationship between two variables or the relationship between a variable and a constant There are six relational operators (=,,,!=,=,=) ©NIIT PLT/Lesson 2/Slide 12 of 33
13. 13. Representing the Logic of Programs with Conditions Using Operators Logical operators Logical operators (AND, OR, NOT) are used to combine expressions containing relational operators ® nNum1 = 7 AND nNum2 5 ® nNum1 = 7 OR nNum2 5 ® NOT nNum2 = 5 Precedence of the execution of logical operators are NOT, AND, and OR. ©NIIT PLT/Lesson 2/Slide 13 of 33
14. 14. Representing the Logic of Programs with Conditions Just a Minute… Draw a flowchart to accept item name, price, and quantity. You need to calculate value as the product of price and quantity, and display the calculated value and the item name using variables. ©NIIT PLT/Lesson 2/Slide 14 of 33
15. 15. Representing the Logic of Programs with Conditions Representing Decisions in a Flowchart Many problems require decisions to be made All decisions may or may not state an action to be taken if the condition is false ©NIIT PLT/Lesson 2/Slide 15 of 33
16. 16. Representing the Logic of Programs with Conditions Representing Decisions in a Flowchart Flowchart Segment to Compare Two Numbers and Check for Equality Is nNum1 = No nNum2 ? Yes Display “The Display “The numbers are numbers are equal” not equal” ©NIIT PLT/Lesson 2/Slide 16 of 33
17. 17. Representing the Logic of Programs with Conditions Example Accept two numbers and print the larger of the two numbers. Start numeric nNum1, nNum2 Accept nNum1 Accept nNum2 A ©NIIT PLT/Lesson 2/Slide 17 of 33
18. 18. Representing the Logic of Programs with Conditions Example (Contd.) A Is Yes Display “ The nNum1=nNum2? numbers are equal” No Is Yes nNum1nNum2? Display nNum1 No Display nNum2 Stop ©NIIT PLT/Lesson 2/Slide 18 of 33
19. 19. Representing the Logic of Programs with Conditions Example Print the value of nX only if the value of nX is greater than 10 and nX is an even number. Start numeric nX Accept nX Is No nX10 AND nX%2=0? Yes Display nX Stop ©NIIT PLT/Lesson 2/Slide 19 of 33
20. 20. Representing the Logic of Programs with Conditions Example Accept the year and then determine whether the year is a leap year or not. A leap year is one that is divisible by 4, other than a century year, such as 1900. A century year, which is divisible by 400, such as 2000, is also a leap year. To evaluate the given condition, we can interpret this as: If year is divisible by 4 AND not divisible by 100 OR divisible by 400, it is a leap year. ©NIIT PLT/Lesson 2/Slide 20 of 33
21. 21. Representing the Logic of Programs with Conditions Flowchart to Determine the Leap Year Start numeric nYear Display “ Please enter a year” Accept nYear A ©NIIT PLT/Lesson 2/Slide 21 of 33
22. 22. Representing the Logic of Programs with Conditions Flowchart to Determine the Leap Year (Contd.) A Is nYear % 4=0 AND No Display “ This is (nYear % 100 !=0 OR not a leap year” nYear % 400=0) ? Yes Display “This is a leap year” Stop ©NIIT PLT/Lesson 2/Slide 22 of 33
23. 23. Representing the Logic of Programs with Conditions Example To decide about the discount percentage on a TV, the sales person needs to check the type of TV. If the TV is Black and White [B], the discount will be 5 percent of the selling price. If the type of TV is colored[C], then he has to verify the size of TV screen. For 14 inches screen, discount is 8 percent of the selling price and for 21 inches screen, the discount is 10 percent of the selling price. ©NIIT PLT/Lesson 2/Slide 23 of 33
24. 24. Representing the Logic of Programs with Conditions Flowchart to Calculate Discount Start numeric nScreen, nDiscount character cType Accept cType Accept nScreen Is Yes cType=‘B’? nDiscount=5% of SP No Is Yes Is Yes nDiscount=8% of SP cType=‘C’? nScreen=14? No No Is Yes nDiscount=10% of SP nScreen=21? No Stop ©NIIT PLT/Lesson 2/Slide 24 of 33
25. 25. Representing the Logic of Programs with Conditions Problem Statement 2.P.1 Study the given flowchart and answer the following questions. What will be output when: a) nNum=7 b) nNum=3 c) nNum=11 ©NIIT PLT/Lesson 2/Slide 25 of 33
26. 26. Representing the Logic of Programs with Conditions Problem Statement 2.P.1(Contd.) Start numeric nNum Accept nNum Is Yes nNum10? Display “ GOOD” No Is Yes nNum5? Display “OK” No Display “REJECT” Stop ©NIIT PLT/Lesson 2/Slide 26 of 33
27. 27. Representing the Logic of Programs with Conditions Problem Statement 2.P.2 Study the flowchart and answer the following questions. What will be the output when: a) nX=150 and nY=75 b) nX=90 and nY=50 c) nX=40 and nY=80 ©NIIT PLT/Lesson 2/Slide 27 of 33
28. 28. Representing the Logic of Programs with Conditions Problem Statement 2.P.2 (Contd.) Start numeric nX, nY Accept nX Accept nY Is Yes Is Yes nX nY ? nX 100 ? Display “ GOOD” No No Is No nY 100 ? Yes Display nY Stop ©NIIT PLT/Lesson 2/Slide 28 of 33
29. 29. Representing the Logic of Programs with Conditions Problem Statement 2.P.3 Draw a flowchart to accept a number and then find out whether or not the number is divisible by 5. ©NIIT PLT/Lesson 2/Slide 29 of 33
30. 30. Representing the Logic of Programs with Conditions Problem Statement 2.P.4 Draw a flowchart to accept three numbers and display the largest number. ©NIIT PLT/Lesson 2/Slide 30 of 33
31. 31. Representing the Logic of Programs with Conditions Problem Statement 2.P.5 Candidates have to enter their age. The age cannot be negative. If a negative age is entered, an error message has to be displayed, otherwise the age is displayed. Represent the error checking logic for this situation using a flowchart. ©NIIT PLT/Lesson 2/Slide 31 of 33
32. 32. Representing the Logic of Programs with Conditions Summary In this lesson, you learned that: Data can be categorized as a constant or variable Data types can be: Numeric Character The operators are: Arithmetic Relational Logical ©NIIT PLT/Lesson 2/Slide 32 of 33
33. 33. Representing the Logic of Programs with Conditions Summary (Contd.) Arithmetic operators are used to perform arithmetic calculations. The symbols that represents arithmetic operations are called arithmetic operators (*,/,+,-,%). Relational operators are used to test the relationship between two variables. The symbols that represent relational operations are called relational operators (,,=,!=). Logical operators (AND, OR, NOT) are used to combine expressions containing relational operators. The decision box is used to apply conditions by asking a question in a flowchart. ©NIIT PLT/Lesson 2/Slide 33 of 33