C if else Statement (original) (raw)

Last Updated : 18 Oct, 2025

The **if else in C is an extension of the if statement which not only allows the program to execute one block of code if a condition is true, but also a different block if the condition is false.

If the condition is true, then the code inside the if block is executed, otherwise the code inside the else block is executed.
Any non-zero and non-null values are assumed to be true, and zero or null values are assumed to be false. C `

#include <stdio.h>

int main() { int n = 10;

if (n > 5)
{
    printf("%d is greater than 5", n);
}
else
{
    printf("%d is less than 5", n);
}

return 0;

}

Output

10 is greater than 5

**Explanation: In the above program, the condition checks if the variable **n is greater than 5. If true, if block is executed and it prints that n is greater than 5. If it evaluates to false, the else block is executed, printing that n is less than 5. Since n is **10, it prints "10 is greater than 5".

**Working of if-else statement

The below flowchart explains the if else works in C:

flowchart of if-else statement in C

Flowchart of if-else in C

The **if-else statement works by checking the condition defined with the if statement.
If the condition defined in the if statement is true, then the code inside the if block is executed and the rest is skipped.
If the condition evaluates to false, then the program executes the code in the else block

**Negative Number check using If-else statement

C `

#include <stdio.h>

int main() { int n = -7;

// If the number is negative
if (n < 0)
    printf("Negative");

// If the number is not negative
else
    printf("Not Negative");

return 0;

}

**Explanation: In this program, the if statements check if the given number **n is less than 0 which means that the number is negative. As **n is negative, it prints the if block. But if the number **n was positive, the else block would have been executed.

**Note: If long at the block only contains the single statement, we can skip the curly braces.

**Check if Integer Lies in the Range

C `

#include <stdio.h>

int main() { int n = 6;

// Check if the number lies in the range [10, 20]
if (n >= 10 && n <= 20)
{
    printf("%d lies in range.", n);
}
else
{
    printf("%d does not lie in range.", n);
}

return 0;

}

Largest Among Three Numbers Using If-else

C `

#include <stdio.h>

int main() { int a = 1, b = 2, c = 11;

// Finding the largest by comparing using relational operators with if-else
if (a >= b)
{
    if (a >= c)
        printf("%d", a);
    else
        printf("%d", c);
}
else
{
    if (b >= c)
        printf("%d", b);
    else
        printf("%d", c);
}

return 0;

}

Try It Yourself