/* ---------------------------------- */
/* save as c17d.c                     */
/* ---------------------------------- */
#include  "x_hfile.h"
#include       "fd.h"
/* ---------------------------------- */
int main(void)
{
double a,b,n,
       ay,by,ny,
       Mxy,Myx;

 clrscrn();
 printf(" f : (x,y)-> %s\n\n\n", feq);

 a = 1;         ay = -1; 
 b = 4;         by =  2; 
 n = 2*10;     ny  = 2*10;


 Myx = simpson_dydx(f,a,  b,  n,
                        ay, by, ny);

 Mxy = simpson_dxdy(f,a,  b,  n, 
                        ay, by, ny);


 printf(" With the simpsonal's rule.\n\n");
 printf("    (%.3f  (%.3f\n",     b, by);
 printf(" int(   int(       %s  Dy Dx = %.6f\n", feq, Myx);
 printf("    (%.3f  (%.3f\n\n\n", a, ay);
 
 printf("    (%.3f  (%.3f\n",     by, b);
 printf(" int(   int(       %s  Dx Dy = %.6f\n", feq, Mxy);
 printf("    (%.3f  (%.3f\n\n\n", ay, a);

 stop();

 return 0;
}
/* ---------------------------------- */