#include <iostream.h>
#include <math.h>
#include <iomanip.h>
#include <stdlib.h>
#include <fstream.h>
#include <string>
#include <process.h>

void main()
{
    //program d4r28
    //driver for routine ex
    int i;
	char text[20];
    double nval,value,x; 
    const double pi = 3.1415926;
    fstream fin;
    fin.open("d:\\vc常用數(shù)值算法集\\data\\fncval.dat",ios::in);
    while ( strcmp(text,"Exponential")!=0 )
	{
      fin>>text;
	}
	fin>>text;
	fin>>text;
    fin>>nval; 
    cout<<"Exponential integral Ex "<<endl;
    fin>>text;
    cout<<endl;
    cout<<"    x            actual             Ex(x)"<<endl;
    for( i = 1; i<=nval; i++)
	{
        fin>>x;
		fin>>value;           
		cout<<setw(6)<<x;
        cout<<setw(18)<<value;
		cout<<setw(18)<<ex(x)<<endl;			          
    }
}