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C program to find the sum of main and opposite diagonal elements of a matrix

Here, we are going to learn how to find the sum of main and opposite diagonal elements of a matrix in C programming language?
Submitted by Nidhi, on July 14, 2021

Problem statement

Given a matrix, we have to find the sum of main and opposite diagonal elements of a matrix using C program.

Finding sum of main and opposite diagonal elements of a matrix

The source code to find the sum of the main and opposite diagonal elements is given below. The given program is compiled and executed using GCC compile on UBUNTU 18.04 OS successfully.

C program to find the sum of main and opposite diagonal elements of a matrix

// C program to find the sum of main and opposite diagonal elements

#include <stdio.h>

int main()
{
    int Matrix[3][3] = {
        { 9, 8, 7 },
        { 5, 4, 6 },
        { 1, 2, 3 }
    };

    int i, j, sum1 = 0, sum2 = 0;

    printf("Matrix:\n");
    for (i = 0; i < 3; ++i) {
        for (j = 0; j < 3; ++j) {
            printf(" %d", Matrix[i][j]);
        }
        printf("\n");
    }

    for (i = 0; i < 3; ++i) {
        sum1 = sum1 + Matrix[i][i];
        sum2 = sum2 + Matrix[i][3 - i - 1];
    }

    printf("Sum of Main diagonal elements: %d\n", sum1);
    printf("Sum of Opposite diagonal elements: %d\n", sum2);

    return 0;
}

Output

Matrix:
 9 8 7
 5 4 6
 1 2 3
Sum of Main diagonal elements: 16
Sum of Opposite diagonal elements: 12

Explanation

Here, we created a 3X3 matrix matrix using the 2D array. Then we find the sum of main and opposite diagonal elements. After that, we printed the Matrix and the sum of diagonals on the console screen.

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