#include <stdio.h>

void summa(double a[3][3], double b[3][3], double c[3][3])
{
  int i,j;
  for (i=0; i<3; i++)
    for (j=0; j<3; j++)
      c[i][j] = a[i][j] + b[i][j];
}


double rivi_x_sarake(double a[3][3], int i,  double b[3][3], int j)
{
  double s=0.0;
  int k;
  for (k=0; k<3; k++)
    s += a[i][k]*b[k][j];
  return s;
}


void tulo(double a[3][3], double b[3][3], double c[3][3])
{
  int i,j;
  for (i=0; i<3; i++)
    for (j=0; j<3; j++)
      c[i][j] = rivi_x_sarake(a,i,b,j);

}

void tulosta_mat(double a[3][3])
{
  int i,j;
  for (i=0; i<3; i++) {
    for (j=0; j<3; j++)
      printf("%6.1lf ",a[i][j]);
    printf("\n");
  }
}

int main(void)
{
  double a[3][3] = { {1,2,3},
                     {4,5,6},
                     {7,8,9}
                   };
  double b[3][3] = { {1,0,2},
                     {0,0,3},
                     {2,0,1}
                   };
  double c[3][3];
  
  summa(a,b,c);   tulosta_mat(c);
  tulo(a,b,c);    tulosta_mat(c);
                                         
  return 0;
}