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

void main()
{
    //program d4r14
    //driver for routine bessj0
    int i;
	char text[20];
    double nval,actual,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,"Bessel")!=0)
	{
      fin>>text;
	}
	fin>>text;
	fin>>text;
    fin>>nval; 
    cout<<"Bessel Function J0 "<<endl;
    fin>>text;
    cout<<endl;
    cout<<"     x        actual         bessj0(x)"<<endl;
    for( i = 1;i<=nval;i++)
	{
        fin>>x;
		fin>>actual;           
		cout<<setprecision(4)<<setw(6)<<x;
		cout<<setprecision(7)<<setw(16)<<actual;
		cout<<setprecision(7)<<setw(16)<<bessj0(x)<<endl;			          
    }
}