Example: Print Diagonal Elements of a Square Matrix in C

// Print Diagonal Elements of a Square Matrix
#include <stdio.h>

int main() {
    // Step 1: Define the square matrix and its size
    int size = 3; // For a 3x3 matrix
    int matrix[3][3] = {
        {1, 2, 3},
        {4, 5, 6},
        {7, 8, 9}
    };

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

    // Step 2: Print Primary Diagonal elements
    printf("Primary Diagonal elements: ");
    for (int i = 0; i < size; i++) {
        // Elements on the primary diagonal have row index 'i' equal to column index 'j'
        printf("%d ", matrix[i][i]);
    }
    printf("\n");

    // Step 3: Print Secondary Diagonal elements
    printf("Secondary Diagonal elements: ");
    for (int i = 0; i < size; i++) {
        // Elements on the secondary diagonal have row index 'i' + column index 'j' = size - 1
        printf("%d ", matrix[i][size - 1 - i]);
    }
    printf("\n");

    return 0;
}