#include <stdio.h>
void multi_matrix(double b[][2], double c[][2],double x[][2]);
void show_matrix(double mat[][2], char *key);
int main(void){
int i,j;
double c[2][2]={{0.02,0.0},{0.02,0.1}};
double x[2][2]={{1.0,0.0},{0.0,400.0}};
double b[2][2]={{0,0},{0,0}};
multi_matrix(b,c,x);
show_matrix(c,"C");
show_matrix(x,"X");
show_matrix(b,"CX");
return 0;}
void multi_matrix(double b[][2],double c[][2],double x[][2]){
int i,j,k;
for(i=0;i<2;i++){
for(j=0;j<2;j++){
for(k=0;k<2;k++){
b[i][j]+=c[i][k]*x[k][j];}}}}
void show_matrix(double mat[][2], char *key) {
int i,j;
printf("%s\n",key);
for(i=0;i<2;i++) {
for(j=0;j<2;j++) {
printf("%f ",mat[i][j]);}
printf("\n");}}