C Program to Add Two Matrices Using Multi-dimensional Arrays

In this example, you will learn to add two matrices in C programming using two-dimensional arrays.

To understand this example, you should have the knowledge of the following C programming topics:

Program to Add Two Matrices

#include <stdio.h>
int main() {
    int r, c, a[100][100], b[100][100], sum[100][100], i, j;
    printf("Enter the number of rows (between 1 and 100): ");
    scanf("%d", &r);
    printf("Enter the number of columns (between 1 and 100): ");
    scanf("%d", &c);

    printf("\nEnter elements of 1st matrix:\n");
    for (i = 0; i < r; ++i)
        for (j = 0; j < c; ++j) {
            printf("Enter element a%d%d: ", i + 1, j + 1);
            scanf("%d", &a[i][j]);
        }

    printf("Enter elements of 2nd matrix:\n");
    for (i = 0; i < r; ++i)
        for (j = 0; j < c; ++j) {
            printf("Enter element a%d%d: ", i + 1, j + 1);
            scanf("%d", &b[i][j]);
        }

    // adding two matrices
    for (i = 0; i < r; ++i)
        for (j = 0; j < c; ++j) {
            sum[i][j] = a[i][j] + b[i][j];
        }

    // printing the result
    printf("\nSum of two matrices: \n");
    for (i = 0; i < r; ++i)
        for (j = 0; j < c; ++j) {
            printf("%d   ", sum[i][j]);
            if (j == c - 1) {
                printf("\n\n");
            }
        }

    return 0;
}

Output

Enter the number of rows (between 1 and 100): 2
Enter the number of columns (between 1 and 100): 3

Enter elements of 1st matrix:
Enter element a11: 2
Enter element a12: 3
Enter element a13: 4
Enter element a21: 5
Enter element a22: 2
Enter element a23: 3
Enter elements of 2nd matrix:
Enter element a11: -4
Enter element a12: 5
Enter element a13: 3
Enter element a21: 5
Enter element a22: 6
Enter element a23: 3

Sum of two matrices: 
-2   8   7   

10   8   6  

In this program, the user is asked to enter the number of rows r and columns c. Then, the user is asked to enter the elements of the two matrices (of order r*c).

We then added corresponding elements of two matrices and saved it in another matrix (two-dimensional array). Finally, the result is printed on the screen.