////////////////////////////////////////////////////////////////////////////////
// File: testtriplefactorial.c                                                //
//                                                                            //
// Test the functions Triple_Factorial(), Trible_Factorial_Max_Arg(),  and    //
// xTriple_Factorial() in the file triple_factorial.c.                        //
//                                                                            //
////////////////////////////////////////////////////////////////////////////////

#include <math.h>
#include <float.h>
#include <stdio.h>
                                    
                        // Externally defined routines

extern double Triple_Factorial( int n );
extern long double xTriple_Factorial( int n );
extern int    Triple_Factorial_Max_Arg( void );

int main()
{
   double z;
   long double xz;
   int i;
  
   printf("Program: testtriplefactorial.c\n");
   printf("Test Triple_Factorial() \n\n");

   printf("Exceptional values: Argument <= -3, return 0,\n");
   printf("                    Argument > Double_Factorial_Max_Arg() return DBL_MAX\n\n");
   printf("(-3)!!!  %22.16e\n",Triple_Factorial(-3));
   printf("(%3d)!!! %22.16e\n",Triple_Factorial_Max_Arg()+1,Triple_Factorial(Triple_Factorial_Max_Arg() + 1));  
   printf("(%3d)!!! %22.16e\n",Triple_Factorial_Max_Arg()+2,Triple_Factorial(Triple_Factorial_Max_Arg() + 2));  
   printf("\n\nTriple Factorials\n");
   printf("   n!!!   Triple_Factorial(n)  n*Triple_Factorial(n-3)   Relative Error /\n");
   printf("                                                          DBL_EPSILON\n");
   for (i = -2; i <= Triple_Factorial_Max_Arg(); i++) {
      if (i <= 0) z = 1.0;
      else if (i <= 3) z = i;
      else z = Triple_Factorial(i-3) * i;
      printf("%4d!!!  %22.16e %22.16e %10.4f\n",i,Triple_Factorial(i),z,(Triple_Factorial(i)-z)/(Triple_Factorial(i)*DBL_EPSILON));
   }

   printf("\nTest xTriple_Factorial() \n\n");

   printf("Exceptional values: Argument <= -3, return 0,\n");
   printf("                    Argument > Double_Factorial_Max_Arg() return DBL_MAX\n\n");
   printf("(-3)!!!  %22.16Le\n",xTriple_Factorial(-3));
   printf("(%3d)!!! %22.16Le\n",Triple_Factorial_Max_Arg()+1,xTriple_Factorial(Triple_Factorial_Max_Arg() + 1));  
   printf("(%3d)!!! %22.16Le\n",Triple_Factorial_Max_Arg()+2,xTriple_Factorial(Triple_Factorial_Max_Arg() + 2));  
   printf("\n\nxTriple Factorials\n");
   printf("   n!!!   xTriple_Factorial(n) n*xTriple_Factorial(n-3)   Relative Error /\n");
   printf("                                                           DBL_EPSILON\n");
   for (i = -2; i <= Triple_Factorial_Max_Arg(); i++) {
      if (i <= 0) xz = 1.0L;
      else if (i <= 3) xz = (long double)i;
      else xz = xTriple_Factorial(i-3) * (long double)i;
      printf("%4d!!!  %22.16Le %22.16Le %10.4Lf\n",i,xTriple_Factorial(i),xz,(xTriple_Factorial(i)-xz)/(xTriple_Factorial(i)*(long double) DBL_EPSILON));
   }
}