d4r15.cpp

工程算法 这是一个很有用的工程数值算法集锦

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

void main()
{
    //program d4r15
    //driver for routine bessy0
    int i;
	char text[20];
    double nval,actual,x; 
    const double pi = 3.1415926;
    fstream fin;
    fin.open("d:\\vc常用数值算法集\\data\\fncval.dat",ios::in);
    while (strcmp(text,"Y0")!=0)
	{
      fin>>text;
	}
	//fin>>text;
    fin>>nval;
    cout<<"Bessel Function Y0 "<<endl;
    fin>>text;
    cout<<endl;
    cout<<"    x           actual           bessy0(x)"<<endl;
    cout<<setprecision(5)<<setiosflags(ios::fixed);
    for( i = 1;i<=nval;i++)
	{
        fin>>x;
		fin>>actual;           
		cout<<setprecision(1)<<setw(6)<<x;
		cout<<setprecision(7)<<setw(18)<<actual;
		cout<<setprecision(7)<<setw(18)<<bessy0(x)<<endl;			          
    }
}