main (int argc, char **argv) {
  float a[100][100], b[100][100], c[100][100];
  int i,j;
  int n = 100;


 for (j=0; j<n; j+=2)
   for (i=0; i<n; i+=2) {
         a[i][j] = b[i][j] + c[i][j];
         a[i+1][j] = b[i+1][j] + c[i+1][j];

         a[i][j+1] = b[i][j+1] + c[i][j+1];
         a[i+1][j+1] = b[i+1][j+1] + c[i+1][j+1];
   }
}