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Computer ProgrammingModule-4 (Lecture-2)

Virendra Singh ShekhawatDepartment of Computer Science & Information Systems

BITS PilaniPilani Campus

BITS Pilani, Pilani Campus

Topics to be Covered:

Conditional constructs to handle multiple branches

If—else –if , switch—case

Conditional Statements: Multiple Branches

• Conditional statements may have more than one branches

– Add an extra condition i.e. numbers can be equal, in the problem of finding max and min of two numbers.

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numbers.

• If numbers are not equal then only max and min are valid

• Otherwise it should display “The numbers are equal”

3

Conditional Statements: Multiple Branches

• The program fragment for modified problem is as follows:

int x, y, max, min;

scanf(“%d%d”,&x,&y);

if(x!=y)

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if(x!=y)

if(x>y) { max = x; min = y;}

else {max = y; min = x;}

else printf(“Numbers are equal”);

4

Conditional Statements: Multiple Branches

• Extend the max min problem from two numbers to three numbers i.e. x, y and z Exercise:

Convert it into if-else statements

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5

Conditional Statements: Multiple Branches

Consider the problem to print number of days in a given

month

Solution: Using if—else – if if(month==4||month==6||month==9||month==11)

printf(“Month has 30 days”);

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printf(“Month has 30 days”);else if (month == 1||month == 3||month == 5||month == 7||

month == 8||month == 10||month == 12)printf(“Month has 31 days”);

else if (month == 2)

printf(“Month has 28 or 29 days”);

else

printf(“Invalid month value”);

6

switch –case Statement: Multiple Branches

int month;

scanf(“%d”,&month);

switch(month) {

case 4: case 6: case 9: case 11: printf(“ 30 days”); break;

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case 1: case 3: case 5: case 7: case 8: case 10: case 12:

printf(“31 days”); break;

case 2: printf(“28 or 29 days”); break;

default: printf(“ Not a valid month”);

}

7

Switch –case Statement in C

• For multiple branches with simple uniform conditions, switch-case statement can be used

– The conditions must be in the form of equality (i.e. x == c) on Integer/character

– The break statement is used to indicate that the

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– The break statement is used to indicate that the next case need not be tested

– If none of the cases match then the default case is executed

8

Switch Statement: Flow Chart

switch( )exprcase 1

case 2

Statement Block-1; break;

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9

case 3

case 4

default

Statement Block-3; break;

Statement Block-4; break;.....

Default Statement Block;

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BITS Pilani, Pilani Campus

Thank You!