Matrix Addition in C

Arrays

Add corresponding entries of two small matrices using nested loops.

Complete program

#include <stdio.h>

int main(void) {
    int a[2][2] = {{1, 2}, {3, 4}};
    int b[2][2] = {{5, 6}, {7, 8}};
    int result[2][2];
    for (int row = 0; row < 2; ++row) {
        for (int col = 0; col < 2; ++col) {
            result[row][col] = a[row][col] + b[row][col];
            printf("%d%s", result[row][col], col == 1 ? "\n" : " ");
        }
    }
    return 0;
}

Try in Circuit →

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How it works

Matrix addition requires the same dimensions on both sides. The outer loop selects a row; the inner loop selects each column within that row.

The result is another two-dimensional array. This is element-wise addition, not matrix multiplication. Change the dimensions consistently in declarations and loop bounds when experimenting; a wrong bound can access unrelated memory.

Expected output

6 8
10 12

Concepts to practice

• Multidimensional arrays
• Nested loops
• Dimensions

Predict a different input or change one value, then compare the result with your prediction. Keep changes within the documented bounds and read warnings before trusting an answer.