C if. .else Statement.

C if. .else Statement.

C if Statement

 The syntax of the if statement in C programming is:

Syntax :

if (test expression) {
// statements to be executed if the test expression is true
}

How if statement works?

1: The if statement evaluates the test expression inside the parenthesis ().

2: If the test expression is evaluated to true, statements inside the body of if are executed.

3: If the test expression is evaluated to false, statements inside the body of if are not executed.

Example 1: if statement

#include <stdio.h> 

void main()
{
int x,y;

printf("Enter the Value of x: ");
scanf("%d",&x);

printf("Enter the Value of y: ");
scanf("%d",&y);

if (x<y) {
printf("\n%d is less than %d",x,y);
}
}

OUTPUT:-

Enter the Value of x: 10

Enter the Value of y: 20

10 is less than 20

  Program File:(click the following .c file to get the program file)    

 

                      If-statement.c

C if...else Statement

 

  The if statement may have an optional else block. The syntax of the if..else statement is:

Syntax :

 

 if (test expression) {

// statements to be executed if the test expression is true
}
else {
// statements to be executed if the test expression is false
}

How if...else statement works?

1: If the test expression is evaluated to true,

statements inside the body of if are executed.

statements inside the body of else are skipped from execution.

2: If the test expression is evaluated to false,

statements inside the body of else are executed

statements inside the body of if are skipped from execution.

Example 2: if..else statement

#include <stdio.h>
void main () {
int a;
printf("Enter the Value of a: ");
scanf("%d",&a);

/* check the boolean condition */
if( a < 20 ) {
/* if condition is true then print the following */
printf("%d is less than 20\n",a);
}
else {
/* if condition is false then print the following */
printf("%d is not less than 20\n",a);
}
}

OUTPUT:-

   

  Output 1:

    Enter the Value of a: 10

       10 is less than 20

Output 2:

    Enter the Value of a: 100

       100 is not less than 20

 

 Program File:(click the following .c file to get the program file)    

               If-else-statement.c

 

C if...else Ladder

 

 Syntax of if...else Ladder:

  if (test expression1) {

// statement(s)
}
else if(test expression2) {
// statement(s)
}
else if (test expression3) {
// statement(s)
} . .
else {
// statement(s)
}

Example 3: C if...else Ladder 

#include<stdio.h>

void main(){

int n;

printf("Enter the Value of n: ");
scanf("%d",&n);

if(n<18){
printf("\nYou are not able for driving");
}
else if(n>18){
printf("\nYou are able for driving");
}
else{
printf("\nInvalid choice");
}
}

OUTPUT:-

   

 Output 1:

Enter the Value of n: 25

You are able for driving

 Output 2:

Enter the Value of n: 10

You are not able for driving

Program File:(click the following .c file to get the program file)    

              If-else-ladder.c