#include <iostream>
#include <string>
#include <math.h>
#include <fstream>
using namespace std;
class CSpectrum{
	public:
		double R,I,Wmax;
		double Emax,I;
	    static double mec2;
	public:
		double Subspec();
		void Spec();
};
double CSpectrum::mec2=0.51;
//function-----OK
double Subspec(double W,double Wmax_,int Z_){
	double mec2=0.51;
	double alpha=1/137.0359895;
	if(1-TMath::Power(alpha*Z_,2)>0){
		double gamma=TMath::Power(1-TMath::Power(alpha*Z_,2),0.5);
		if(TMath::Power(W,2)-TMath::Power(mec2,2)>0){
			double y=alpha*Z_*W*TMath::Power(TMath::Power(W,2)-TMath::Power(mec2,2),-0.5);
			double f;
			f=W*TMath::Power(Wmax_-W,2)*TMath::Power(TMath::Power(W,2)-TMath::Power(mec2,2),gamma-0.5)*TMath::Exp(TMath::Pi()*y)*TMath::Power(TMath::Abs(TMath::Gamma(y)),2);
		}
	}
	return f;
}
	
CSpectrum::Spec(){
	TCanvas *c=new TCanvas();
	ifstream fp1("Udata.dat");
	int Inline =0;
	int n=Inline+1;
	std::string line;
	TF1 *f[4];
	
	//read data-------OK
    while(getline(fp1, line))
     {
       std::stringstream ss(line);
       ss >> Emax>> I; 
	  // cout<<Emax<<endl;
	   

       if(Inline<1){   //------OK
		   //cout<<I<<endl;
		   Wmax=Emax+0.51;
		   //cout<<Emax<<endl;
		   cout<<Wmax<<endl;
		   TF1 *f1=new TF1("f1","CSpectrum::Subspec(x,[0],[1])",0,4);//U's nuclear charge is 92, use parameters
		   f1->SetParameter(0,Wmax);// Wmax is OK
		   f1->SetParameter(1,92);
		   f1->SetLineColor(n+2);
	       f1->Draw();
	   }
	   
	   if(Inline>=1){
		   cout<<Emax<<endl;
		   Wmax=Emax+0.51;
		   f[n]=new TF1("f[n]","CSpectrum::Subspec(x,[0],[1])"0,4);//Po's nuclear charge is 84
		   f[n]->SetParameter(1,Wmax);
		   f[n]->SetParameter(2,84);
		   f[n]->SetLineColor(n+2);
		   f[n]->Draw("same");
		}
		Inline++;
	 }
}