#include <stdio.h>

int a[3][3] = {{1, 3, 5}, {2, -2, 1}, {1, 4, 7}};
int b[3][3] = {{6, 2, 1}, {8, -3, 5}, {2, 4, 1}};
int c[3][3] = {0};

void mat_mult(int a[3][3], int b[3][3]);

int main(void)

{
/* The following lines just reproduce the 'a' and 'b' matrices and present */
/* them in the 3x3 format. This wasn't requested, but it looked neat. :)   */

	printf("\nThis program multiplies the following two matrices.\n");
	
	printf("\n     |%2d %2d %2d|\n", a[0][0], a[0][1], a[0][2]);
	printf("a =  |%2d %2d %2d|\n", a[1][0], a[1][1], a[1][2]);
	printf("     |%2d %2d %2d|\n", a[2][0], a[2][1], a[2][2]);
	
	printf("\n     |%2d %2d %2d|\n", b[0][0], b[0][1], b[0][2]);
	printf("b =  |%2d %2d %2d|\n", b[1][0], b[1][1], b[1][2]);
	printf("     |%2d %2d %2d|\n", b[2][0], b[2][1], b[2][2]);
	
/* Function call for 'c' */

	mat_mult(a, b);	
	
	return 0;
}

/* Function to produce the product matrix 'c' */

void mat_mult(int a[3][3], int b[3][3])
{
	printf("\n --------------------------\n");
	printf("|  and the answer is....   |\n");
	printf(" --------------------------\n");
	
	
/* The following lines produce the numbers to fill the 'c' 3x3 array */
	
	c[0][0] = a[0][0] * b[0][0] + a[0][1] * b[1][0] + a[0][2] * b[2][0];
	c[0][1] = a[0][0] * b[0][1] + a[0][1] * b[1][1] + a[0][2] * b[2][1];
	c[0][2] = a[0][0] * b[0][2] + a[0][1] * b[1][2] + a[0][2] * b[2][2];
	c[1][0] = a[1][0] * b[0][0] + a[1][1] * b[1][0] + a[1][2] * b[2][0];
	c[1][1] = a[1][0] * b[0][1] + a[1][1] * b[1][1] + a[1][2] * b[2][1];
	c[1][2] = a[1][0] * b[0][2] + a[1][1] * b[1][2] + a[1][2] * b[2][2];
	c[2][0] = a[2][0] * b[0][0] + a[2][1] * b[1][0] + a[2][2] * b[2][0];
	c[2][1] = a[2][0] * b[0][1] + a[2][1] * b[1][1] + a[2][2] * b[2][1];
	c[2][2] = a[2][0] * b[0][2] + a[2][1] * b[1][2] + a[2][2] * b[2][2];
	
/* The following three lines produce the product matrix in the 3x3 format for viewing */
	
	printf("\n     |%3d %3d %3d|\n", c[0][0], c[0][1], c[0][2]);
	printf("c =  |%3d %3d %3d|\n", c[1][0], c[1][1], c[1][2]);
	printf("     |%3d %3d %3d|\n", c[2][0], c[2][1], c[2][2]);
	
	return ;
}