If Else Statements in C

The if statement in C language is used to perform operation on the basis of condition. By using if-else statement, you can perform operation either condition is true or false.

There are many ways to use if statement in C language:

  • If statement
  • If-else statement
  • If else-if ladder
  • Nested if

If Statement

The single if statement in C language is used to execute the code if condition is true. The syntax of if statement is given below:

 
  • if(expression){  
  • //code to be executed  
  •  

Flowchart of if statement in C

 

Let’s see a simple example of c language if statement.

if else in C

 
  • #include<stdio.h>    
  • int main()
  • {    
  • int number=0;    
  • printf(“enter a number:”);    
  • scanf(“%d”,&number);    
  • if(number%2==0){    
  • printf(“%d is even number”,number);    
  • }    
  • return 0;  
  • }    

Output

enter a number:4
4 is even number
enter a number:5

 

If-else Statement

The if-else statement in C language is used to execute the code if condition is true or false. The syntax of if-else statement is given below:

 
  • if(expression){  
  • //code to be executed if condition is true  
  • }else{  
  • //code to be executed if condition is false  
  •  

 

Let’s see the simple example of even and odd number using if-else statement in C language.

 
  • #include<stdio.h>    
  • int main()
  • {    
  • int number=0;    
  • printf(“enter a number:”);    
  • scanf(“%d”,&number);     
  • if(number%2==0){    
  • printf(“%d is even number”,number);    
  • }    
  • else{    
  • printf(“%d is odd number”,number);    
  • }     
  • return 0;  
  • }    

Output

enter a number:4
4 is even number
enter a number:5
5 is odd number

If else-if ladder Statement

The if else-if statement is used to execute one code from multiple conditions. The syntax of if else-if statement is given below:

 
  • if(condition1){  
  • //code to be executed if condition1 is true  
  • }
  • else if(condition2)
  • {  
  • //code to be executed if condition2 is true  
  • }  
  • else if(condition3)
  • {  
  • //code to be executed if condition3 is true  
  • }  
  • …  
  • else
  • {  
  • //code to be executed if all the conditions are false  
  •  

Flowchart of else-if ladder statement in C

 

The example of if-else-if statement in C language is given below.

 
  1. #include<stdio.h>    
  2. int main(){    
  3. int number=0;    
  4. printf(“enter a number:”);    
  5. scanf(“%d”,&number);     
  6. if(number==10){    
  7. printf(“number is equals to 10”);    
  8. }    
  9. else if(number==50){    
  10. printf(“number is equal to 50”);    
  11. }    
  12. else if(number==100){    
  13. printf(“number is equal to 100”);    
  14. }    
  15. else{    
  16. printf(“number is not equal to 10, 50 or 100”);    
  17. }    
  18. return 0;  
  19. }    

Output

enter a number:4
number is not equal to 10, 50 or 100
enter a number:50
number is equal to 50