#include <stdio.h>
#include <iostream.h>
#include <math.h>
#define  begin {
#define  end  }

typedef double (*FPtr) (double);

class Fcn{
public:
  Fcn(FPtr f, double a1, double b1);
  FPtr F;
  double a,b,root,froot,error;
  int no_iterations;
  int bisect();
  void writeout (int status);
	 };


  Fcn::Fcn(FPtr f, double a1, double b1){
	 F=f;
	 a = a1;
	 b = b1;
	 }


 int Fcn::bisect() {

  double  a1, b1, ya, yb, yc, c;

  no_iterations = 0;  // Initialize iteration counter
  cout << "\n Start again\n";
 a1= a; b1 = b;
  ya=F(a1);   // function values at x1 and x2
  yb=F(b1);
  if (ya*yb > 0)
		return(2);
  while (no_iterations <= 100)
	  {
	  no_iterations++;
	  c= (a1+b1)/2;
	  yc=F(c);
	  if (yc==0)
		begin
		 a1 = c;
		 b1 = c;
		end
	  else
		if (yb*yc>0)
		 begin
			 b1 = c;
			 yb = yc;
		 end
		else
		 begin
			 a1 = c;
			 ya = c;
		 end
		if ((b1-a1)&& sqrt(F(c)*F(c)) < 1e-15)
		 begin
			 root = (a1+b1)/2;
			 froot = F(c);
			 error = ((b1-a1)/2);
		return(1);
	  end
 }  // end of while
  return(0);
} // end of function

  void Fcn::writeout(int status) {
	switch(status){
	 case 1:
		cout<<"\na= "<<a;
		cout<<"\nb= "<<b;
		cout<<"\nroot= "<<root;
		cout<<"\nfroot= "<<froot;
		cout<<"\nerror= "<<error;
		cout<<"\nno of iterations= "<<no_iterations;
	 break;
	 case 2:
	 cout<<"Sorry no solution since f(a) and f(b) have equal signs";
	 break;
	 case 0:
	 cout<<"Sorry no solution since max no. of iterations exceeded";
	 break;
	 default:
	 cout<<"Trouble somewhere";
	}
	}

  double f1(double x) {
  return (2*x*x+1);
	 }

  double f2(double x) {
  return (x*x-2);
	 }

  int main() {
  int s;
  double a=0;
  double b=2;
  Fcn Froot1(f1,a,b);
  s=Froot1.bisect();
  Froot1.writeout(s);
  Fcn Froot2(f2,a,b);
  s=Froot2.bisect();
  Froot2.writeout(s);
  return(0);}