C Program to multiply two matrices

#include <stdio.h>
#define N 4
 

void multiply(int mat1[][N], int mat2[][N], int res[][N])
{
    int i, j, k;
    for (i = 0; i < N; i++)
    {
        for (j = 0; j < N; j++)
        {
            res[i][j] = 0;
            for (k = 0; k < N; k++)
                res[i][j] += mat1[i][k]*mat2[k][j];
        }
    }
}
 
int main()
{
    int mat1[N][N] = { {1, 1, 1, 1},
                    {2, 2, 2, 2},
                    {3, 3, 3, 3},
                    {4, 4, 4, 4}};
 
    int mat2[N][N] = { {1, 1, 1, 1},
                    {2, 2, 2, 2},
                    {3, 3, 3, 3},
                    {4, 4, 4, 4}};
 
    int res[N][N]; 
    int i, j;
    multiply(mat1, mat2, res);
 
    printf("Result matrix is \n");
    for (i = 0; i < N; i++)
    {
        for (j = 0; j < N; j++)
           printf("%d ", res[i][j]);
        printf("\n");
    }
 
    return 0;
}