C program to check whether a number is even or odd

This C program checks whether the entered number is even or odd. Same algorithm is used to check whether a given number is even or odd.

Prerequisite knowledge:

• A number is even if it is a multiple of 2, and odd if its not.
• Remainder is calculated using the modulus operator (%).
• Basic C programming syntax.

Program: C program to check whether a number is even or odd without using function

#include<stdio.h>
int main()
{
    int a;
    printf("Enter a number: ");
    scanf("%d",&a);
    if((a%2)==0)
        printf("\nEntered number is EVEN!!!\n");
    else
        printf("\nEntered number is ODD!!!\n");
    return 0;
}

% operator is used to find remainder when first number is divided by the second number.

Output:

Enter a number: 59

Entered number is ODD!!!

Program: C program to check whether a number is even or odd using function

In this program, the number is checked for even/odd using bitwise operator. To write a program without using bitwise operator, follow the next code snippet.

#include<stdio.h>
int isEven(int);
int main()
{
    int a;
    printf("Enter a number: ");
    scanf("%d",&a);
    if(isEven(a))
        printf("\nEntered number is EVEN!!!\n");
    else
        printf("\nEntered number is ODD!!!\n");
    return 0;
}


int isEven(int a)
{
    return !(a & 1);
}

Program: Even odd program in C using function – II

#include<stdio.h>
int isEven(int);
int main()
{
    int a;
    printf("Enter a number: ");
    scanf("%d",&a);
    if(isEven(a))
        printf("\nEntered number is EVEN!!!");
    else
        printf("\nEntered number is ODD!!!\n");
    return 0;
}


int isEven(int a)
{
    return (a % 2 == 0);
}

Output:

Sample output 1:

Enter a number: 343

Entered number is ODD!!!

Sample output 2:

Enter a number: 434

Entered number is EVEN!!!

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