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C program to find the missing number in the array using the bitwise XOR operator

Here, we are going to learn how to find the missing number in the array using the bitwise XOR operator in C programming language?
Submitted by Nidhi, on July 11, 2021

Problem statement

Here, we will create an array of integers then we will find the missing number from the array using the bitwise XOR operator.

Finding the missing number in the array using the bitwise XOR operator

The source code to find the missing number in the array using the bitwise XOR operator is given below. The given program is compiled and executed using GCC compile on UBUNTU 18.04 OS successfully.

C program to find the missing number in the array using XOR operator

// C program to find the missing number in array
// using bitwise XOR operator

#include <stdio.h>

int main()
{
    int arr[] = { 1, 2, 3, 5, 6 };

    int n1 = 0;
    int n2 = 0;
    int i = 0;

    n1 = arr[0];

    for (i = 1; i < 4; i++)
        n1 = n1 ^ arr[i];
    for (i = 2, n2 = 1; i <= 5; i++)
        n2 = n2 ^ i;
    n2 = n2 ^ n1;

    printf("Missing element in array is: %d\n", n2);

    return 0;
}

Output

Missing element in array is: 4

Explanation

Here, we created an array arr with 5 elements. Here we also created three variables n1, n2, i that are initialized with 0. Then we found missing elements from the array using the bitwise XOR operator and printed the result on the console screen.

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