C Program to check whether a number is odd or even

For a better understanding of this C program example, we always recommend you to learn the basic topics of C programming listed below:

How to check odd or even number

This C program is to check whether a number is an odd or even number. The logic behind this program is to divide the number by two until it cannot be further divisible, and check for the remainder and see if it is zero or one. For checking this in C language, we use the "MOD operator" which divides the number with 2 until it cannot be further divisible. Finally, if the remainder is one the given number is odd else even.

The user has to input an Integer using printf and scanf statements. Now we use the Mod operator to check the remainder whether zero or one and print the output. Let's take some simple examples to understand more about this.

  1. If the entered number is odd:

    Let the entered value be 'a' = 5. According to the logic, we described the program if '(a%2 = 0)',then a is an even number otherwise odd. Here 'a = 5',then we have (5%2 not equal to zero),so the given number is odd

  2. If the entered number is even:

    Let entered value 'a = 6'. In accordance with the program if (a%2 == 0),then a is an even number otherwise odd. Here 'a = 6',then we have (6%2 = 0),so the given number is even.

How we check odd or even number using the C program

Let us check how we have implemented this logic in C, after importing the header libraries we accept the number from the user and save that into a variable. After that, we use the mod operator to divide the number by 2 and check if the remainder is zero or not using 'if operator'. If the remainder is zero then print its an even number else it's an odd number. 

ALGORITHM

STEP 1: Import the header libraries into the C program to use the built-in Functions. 

STEP 2: Start the main() to start the execution of the program,

STEP 3: Initialize the variables for the remainder and user input values using int datatype.

STEP 4: Accept the number from the user using printf and scanf and save that in a variable. 

STEP 5: Use the mod operator with 2 and store the value of the remainder in a variable.

STEP 6: Use the if condition to check the remainder is zero or not. if the remainder is zero then print its an even number, else print its an odd number.

C Source Code

                                          #include <stdio.h>

void main() {

  int ival, remainder;
  printf("Enter an integer :");
  scanf("%d", & ival);
  remainder = ival % 2;
  if (remainder == 0)
    printf("%d, is an even integer\n", ival);
  else
    printf("%d, is an odd integer\n", ival);
}
                                      

OUTPUT

Enter an integer:13
13, is an odd integer

RUN2

Enter an integer:24
24, is an even integer