Download to read offline
Conditional Statements in C.pptx
- 1. Conditional Statements in C Dr.Surbhi Gupta
- 2. Objectives In this lectureyou will: Learn about control structures Discover how to use the selection control structures if, if...else, and switch in a program 2
- 3. Control Structures Acomputer can proceed: In sequence Selectively (branch) - making a choice Repetitively (iteratively) - looping Some statements are executed only if certain conditions are met A condition is represented by a logical (Boolean) expression that can be true or false A condition is met if it evaluates to true 3
- 5. One-Way (if) Selection The syntax of one-way selection is: if (expression) statement Statement is executed if the value of the expression is true Statement is bypassed if the value is false; program goes to the next statement 5
- 9. Example 3.1: Whilepurchasing certain items, a discount of 10% is offered if the quantity purchased is more than 1000. If quantity and price per item are input through the keyboard, write a program to calculate the total expenses
- 10. Example /* Calculation oftotal expenses */ # include <stdio.h> int main( ) { int qty, dis = 0 ; float rate, tot ; printf ( "Enter quantity and rate " ) ; scanf ( "%d %f", &qty, &rate) ; if ( qty > 1000 ) dis = 10 ; tot = ( qty * rate ) - ( qty * rate * dis / 100 ) ; printf ( "Total expenses = Rs. %fn", tot ) ; return 0 ; }
- 11. Two-Way (if…else) Selection Two-way selection takes the form: if (expression) statement1 else statement2 If expression is true, statement1 is executed otherwise statement2 is executed statement1 and statement2 are any C++ statements else is a reserved word 11
- 14. Example 3.3: Ina company an employee is paid as under: If his basic salary is less than Rs. 1500, then HRA = 10% of basic salary and DA = 90% of basic salary. If his salary is either equal to or above Rs. 1500, then HRA = Rs. 500 and DA = 98% of basic salary. If the employee's salary is input through the keyboard write a program to find his gross salary.
- 15. /* Calculation ofgross salary */ # include <stdio.h> int main( ) { float bs, gs, da, hra ; printf ( "Enter basic salary " ) ; scanf ( "%f", &bs ) ; if ( bs < 1500 ) { hra = bs * 10 / 100 ; da = bs * 90 / 100 ; } else { hra = 500 ; da = bs * 98 / 100 ; } gs = bs + hra + da ; printf ( "gross salary = Rs. %fn", gs ) ; return 0 ; }
- 16. Conditional Operator (?:) Conditional operator (?:) takes three arguments (ternary) Syntax for using the conditional operator: expression1 ? expression2 : expression3 If expression1 is true, the result of the conditional expression is expression2. Otherwise, the result is expression3 16
- 17. Example int x, y; scanf ( "%d", &x ) ; y = ( x > 5 ? 3 : 4 ) ; This statement will store 3 in y if x is greater than 5, otherwise it will store 4 in y. The equivalent if-else form would be, if ( x > 5 ) y = 3 ; else y = 4 ;
- 18. Nested if Nesting:one control statement in another An else is associated with the most recent if that has not been paired with an else 18
- 20. Example The marks obtainedby a student in 5 different subjects are input through the keyboard. The student gets a division as per the following rules: Percentage above or equal to 60 - First division Percentage between 50 and 59 - Second division Percentage between 40 and 49 - Third division Percentage less than 40 - Fail Write a program to calculate the division obtained by the student.
- 22. Switch Structures switchstructure: alternate to if-else switch expression is evaluated first Value of the expression determines which corresponding action is taken Expression is sometimes called the selector 22
- 23. Switch Structures (continued) Expression value can be only integral Its value determines which statement is selected for execution A particular case value should appear only once 23
- 25. Switch Structures (continued) One or more statements may follow a case label Braces are not needed to turn multiple statements into a single compound statement The break statement may or may not appear after each statement switch, case, break, and default are reserved words 25
- 26.
- 29. Summary Two selectionstructures: one-way selection and two- way selection The expression in an if or if...else structure is usually a logical expression Switch structure handles multiway selection 29