# include <stdio.h>

int main ( )
{
  double a[2][2] = { {11.0, 12.0}, {21.0, 22.0} };
  double b[2];
  int i;
  int j;
  int m = 2;
  int n = 2;
  double x[2] = { 1.0, 2.0 };

  for ( i = 0; i < m; i++ )
  {
    b[i] = 0.0;
    for ( j = 0; j < n; j++ )
    {
      b[i] = b[i] + a[i][j] * x[j];
    }
    printf ( "  b[%i] = %f\n", i, b[i] );
  }

  return 0;
}