Check Whether a Number is Even or Odd

An even number is an integer that is exactly divisible by 2. Example: 0, 8, -24

An odd number is an integer that is not exactly divisible by 2. Example: 1, 7, -11, 15

Example #1: Program to Check Even or Odd

#include <stdio.h>
int main()
{
    int number;

    printf("Enter an integer: ");
    scanf("%d",&number);

    // True if the number is perfectly divisible by 2
    if(number%2 == 0)
        printf("%d is even.", number);
    else
        printf("%d is odd.", number);

    return 0;
}

Output

Enter an integer: -7
-7 is odd.

In the program, integer entered by the user is stored in variable number.

Then, whether the number is perfectly divisible by 2 or not is checked using modulus operator. If the number is perfectly divisible by 2, test expression number%2 == 0 evaluates to 1 (true) and the number is even.

But if the test expression evaluates to 0 (false), the number is odd.

Example #2: Program to Check Odd or Even Using Conditional Operator

#include <stdio.h>
int main()
{
    int number;

    printf("Enter an integer: ");
    scanf("%d",&number);

    (number%2 == 0) ? printf("%d is even.", number) : printf("%d is odd.", number);

    return 0;
}