Add Two 2-D Matrices in C

This program adds two 2-D matrices of order m x n and displays the resultant matrix.

C Program

#include <stdio.h>

int main() {
    int a[10][10], b[10][10], sum[10][10];
    int m, n, i, j;

    printf("Enter number of rows (m) and columns (n): ");
    scanf("%d %d", &m, &n);

    printf("Enter elements of first matrix:\n");
    for (i = 0; i < m; i++)
        for (j = 0; j < n; j++)
            scanf("%d", &a[i][j]);

    printf("Enter elements of second matrix:\n");
    for (i = 0; i < m; i++)
        for (j = 0; j < n; j++)
            scanf("%d", &b[i][j]);

    for (i = 0; i < m; i++)
        for (j = 0; j < n; j++)
            sum[i][j] = a[i][j] + b[i][j];

    printf("Resultant matrix (sum):\n");
    for (i = 0; i < m; i++) {
        for (j = 0; j < n; j++) {
            printf("%d ", sum[i][j]);
        }
        printf("\n");
    }

    return 0;
}

Explanation

• Both matrices must have the same dimensions (m rows, n columns) for element-wise addition to be valid.
• Nested loops read each matrix row by row, column by column.
• The sum matrix is built by adding corresponding elements: sum[i][j] = a[i][j] + b[i][j].
• A final pair of nested loops prints the result, with a newline after each row so it displays as a proper grid.

Sample Output

Enter number of rows (m) and columns (n): 2 2
Enter elements of first matrix:
1 2
3 4
Enter elements of second matrix:
5 6
7 8
Resultant matrix (sum):
6 8
10 12