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C program to find odd or even number using bitmasking

In this article, we are going to see how to check a number odd or even using bitwise operators?
Submitted by Radib Kar, on December 30, 2018

Problem statement

Write a C program to find odd or even no using bitwise operators.

Solution: We can use bitwise operator here to solve the problem.

Example

    Let n be a number
    n &1 = 0000000d where d is the LSB of n 
    So, 
    If LSB ==1
        It's odd number
    Else
        Even no

To understand the concept of "LSB" & bitwise operators please read: Bitwise Operators and their working with Examples in C

Example:

    Let n be 7 //00000111
    n & 1 = 1 
    00000111(7) & 00000001(1) =00000001 (1)
    Thus it's an odd number
    Let n be 6 //00000110
    N&1=0
    00000110(6) & 00000001(1) =00000000 (0)
    Thus it's an even number

C program to find odd or even number using bitmasking

#include <stdio.h>

int main() {
  int n;

  printf("enter no: ");

  scanf("%d", & n);

  //n&1 actually results in 0000000d where d is your LSB
  if (n & 1 == 1)
    printf("it's odd no"); //for odd no LSB 1
  else
    printf("it's even no"); //for even no LSB 0

  return 0;
}

Output

First run:
enter no: 7
it's odd no

Second run:
enter no: 6
it's even no

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