C program to interchange diagonals of a matrix

Write a C program to read elements in a matrix and interchange elements of primary(major) diagonal with secondary(minor) diagonal. C program for interchanging diagonals of a matrix. Logic to interchange diagonals of a matrix in C programming.

Input matrix elements: 
1 2 3
4 5 6
7 8 9

Matrix after interchanging its diagonal:
3 2 1
4 5 6
9 8 7

Required knowledge

Basic C programming,For loop, Array

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Program to interchange diagonal elements of a matrix

/**
 * C program to interchange diagonals of a matrix
 */
 
#include <stdio.h>
#define MAX_ROWS 3
#define MAX_COLS 3

int main()
{
    int A[MAX_ROWS][MAX_COLS];
    int row, col, size, temp;
 
    /* Input elements in matrix from user */
    printf("Enter elements in matrix of size %dx%d: \n", MAX_ROWS, MAX_COLS);
    for(row=0; row<MAX_ROWS; row++)
    {
        for(col=0; col<MAX_COLS; col++)
        {
            scanf("%d", &A[row][col]);
        }
    }

    size = (MAX_ROWS < MAX_COLS) ? MAX_ROWS : MAX_COLS;
 
    /*
     * Interchange diagonal of the matrix
     */
    for(row=0; row<size; row++)
    {
        col = row;
 
        temp = A[row][col];
        A[row][col] = A[row][(size-col) - 1];
        A[row][(size-col) - 1] = temp;
    }
 
    /*
     * Print the interchanged diagonals matrix
     */
    printf("\nMatrix after diagonals interchanged: \n");
    for(row=0; row<MAX_ROWS; row++)
    {
        for(col=0; col<MAX_COLS; col++)
        {
            printf("%d ", A[row][col]);
        }
 
        printf("\n");
    }
 
    return 0;
}

Enter elements in matrix of size 3x3:
1 2 3
4 5 6
7 8 9

Matrix after diagonals interchanged:
3 2 1
4 5 6
9 8 7

Happy coding 😉