//Trapzint.cpp	//文件二，類實現
#include "Trapzint.h"	//包含類的聲明頭文件
double Trapz::operator ()(double a,double b,double eps) const
{			//積分運算過程，重載為運算符()
	int done(0);	//是Trapz類的虛函數成員
	int n;
	double h,Tn,T2n;
	n=1;
	h=b-a;
	Tn=h*(f(a)+f(b))/2.0;	//計算n=1時的積分值
	while(!done)
	{
		double temp(0.0);
		for(int k=0;k<n;k++)
		{
		      double x=a+(k+0.5)*h;
		      temp+=f(x);
		}
		T2n=(Tn+h*temp)/2.0;	//變步長梯形法計算
		if(fabs(T2n-Tn)<eps) done=1;	//判斷積分誤差
		else	//進行下一步計算
		{
		      Tn=T2n;
		       n*=2;
		       h/=2;
		}
	}
	return T2n;
}
//End of file Trapzint.cpp