// -----------------------------------------------------------
 //   ftab.cpp  Function tabulation  ftab
 // ------------------------------------------------------------

#include <iostream.h>        // Stream library
#include <string.h>          // String library
#include <math.h>            // Math library

// pointer to function double -> double
 typedef double (*fptype1)(double);

  
 // -----------------------------------------------------------
 // function declarations

	 double sqr(double x);

	 void ftab(fptype1 f, char fs[20], double x1, double x2, int nx);

 // ----------------------------------------------------------

void main ()
{
  cout << "  ------------------------ \n";
  cout << "    Welcome to ftab.cpp    \n";
  cout << "  ------------------------\n";

  ftab(sin,"sin",1,2,5);
  ftab(sqr,"sqr",1,2,3);

}


 // -----------------------------------------------------------
 // definition (implementation)

		void ftab(fptype1 f, char fs[20],double x1, double x2, int nx)
		 {
			double dx = (x2-x1)/nx;
			cout << "\n";
			double x, y;
			for (int i = 0; i <= nx; i++)
			 {
				x = x1 + i*dx;
				y = f(x);
				cout << "   " << fs <<
						  "(" << x << ") = " << y << "\n";
			 }
		 }


 	  double sqr(double x) { return x*x; }

 // -----------------------------------------------------------
 /*  output
 ------------------------
   Welcome to ftab.cpp
 ------------------------

  sin(1) = 0.841471
  sin(1.2) = 0.932039
  sin(1.4) = 0.98545
  sin(1.6) = 0.999574
  sin(1.8) = 0.973848
  sin(2) = 0.909297

  sqr(1) = 1
  sqr(1.33333) = 1.77778
  sqr(1.66667) = 2.77778
  sqr(2) = 4

 */