1    void f(int i, int j, int radius, int width, int N)
       2    {
       3      const int diff   = i-radius;
       4      const int lowk   = (diff>0 ? diff : 0 );
       5      int k;
       6    
       7      for(k=lowk; k<= 2; k++){
       8        int idx = ((k-i+radius)*width-j+radius);
       9        if (idx < 0)
      10  	abort ();
      11      }
      12    
      13      for(k=lowk; k<= 2; k++);
      14    }
      15    
      16    
      17    int main(int argc, char **argv)
      18    {
      19      int exc_rad=2;
      20      int N=8;
      21      int i;
      22      for(i=1; i<4; i++)
      23        f(i,1,exc_rad,2*exc_rad + 1, N);
      24      exit (0);
      25    } 
      26