Nested if else in C

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When there are a series of decisions involved, you may have to use more than one if else statements in nested form. The nested condition means condition within the condition.

This is not a new concept, it is a technique to solve the problem. You can use nested if else statement in three ways.

• Nested if else within if-block
• Nested if else within else-block
• Nested if else within both if-block and else-block

Note: C compiler execute program line by line

1. Nested if else within if-block

In this situation, the nested condition is written within the scope of the main if condition.

Syntax

if(condition 1) { if(condition 2) { // statement 1 } else { // statement 2 } } else { // statement 3 }

Example

#include<stdio.h> int main() { int A=20, B=20; if(A>=B) { if(A>B) { printf("A is largest number"); } else { printf("A and B are equal"); } } else { printf("B is largest number"); } return 0; }

Output

A and B are equal

*: You can see, how you have written nested if else statement to solve the problem. Try to solve some more problem by yourself!

2. Nested if else within else-block

In this situation, the nested condition is written within the scope of the main else.

Syntax

if(condition 1) { // statement 1 } else { if(condition 2) { // statement 2 } else { // statement 3 } }

Example

#include<stdio.h> int main() { int mark=55; printf("Result is:\n"); if(mark < 40) { printf("C Grade"); } else { if(mark>=60) { printf("A Grade"); } else { printf("B Grade"); } } return 0; }

Output

Result is : B Grade

3. Nested if else within both if-block and else-block

In this situation, the nested condition is written within the both i.e within if-block and within else-block.

Syntax

if(condition 1) { if(condition 2) { // statement 1 } else { // statement 2 } } else { if(condition 3) { // statement 3 } else { // statement 4 } }

Example

#include<stdio.h> int main() { int a=9, b=11, c=7; if(a>c) { if(a>c) { printf("a is largest number"); } else { printf("c is largest number"); } } else { if(b>c) { printf("b is largest number"); } else { printf("c is largest number"); } } return 0; }

Output

b is largest number

Facts about nested if else statement

• Any level of nested if else allowed in C.
• Any number of nested if else allowed in C.
• Nested if else is a technique to solve the problem.

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