```/* -*- mode: c -*-
* \$Id: matrix.gcc,v 1.6 2001/03/31 15:52:48 doug Exp \$
* http://www.bagley.org/~doug/shootout/
*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#define SIZE 30

int **mkmatrix(int rows, int cols) {
int i, j, count = 1;
int **m = (int **) malloc(rows * sizeof(int *));
for (i=0; i<rows; i++) {
m[i] = (int *) malloc(cols * sizeof(int));
for (j=0; j<cols; j++) {
m[i][j] = count++;
}
}
return(m);
}

void zeromatrix(int rows, int cols, int **m) {
int i, j;
for (i=0; i<rows; i++)
for (j=0; j<cols; j++)
m[i][j] = 0;
}

void freematrix(int rows, int **m) {
while (--rows > -1) { free(m[rows]); }
free(m);
}

int **mmult(int rows, int cols, int **m1, int **m2, int **m3) {
int i, j, k, val;
for (i=0; i<rows; i++) {
for (j=0; j<cols; j++) {
val = 0;
for (k=0; k<cols; k++) {
val += m1[i][k] * m2[k][j];
}
m3[i][j] = val;
}
}
return(m3);
}

int main(int argc, char *argv[]) {
int i, n = ((argc == 2) ? atoi(argv[1]) : 1);

int **m1 = mkmatrix(SIZE, SIZE);
int **m2 = mkmatrix(SIZE, SIZE);
int **mm = mkmatrix(SIZE, SIZE);

for (i=0; i<n; i++) {
mm = mmult(SIZE, SIZE, m1, m2, mm);
}
printf("%d %d %d %d\n", mm[0][0], mm[2][3], mm[3][2], mm[4][4]);

freematrix(SIZE, m1);
freematrix(SIZE, m2);
freematrix(SIZE, mm);
return(0);
}
```