d10r4.cpp

来自「工程算法 这是一个很有用的工程数值算法集锦」· C++ 代码 · 共 37 行

#include <process.h>
#include <math.h>
#include <iomanip.h>
#include <iostream.h>

double func(double x)
{
	double t;
	t=bessj0( x);
	return t;
}

void main()
{   //program d10r4
    //driver for routine rtbis
	int n,nbmax,nb,i;
	double xb1[21], xb2[21],xacc,x1,x2,root;
    n = 100;
    nbmax = 20;
    x1 = 1.0;
    x2 = 50.0;
    nb = nbmax;
    zbrak(x1, x2, n, xb1, xb2, nb);
    cout<<endl;
    cout<<"Roots of Bessj0:"<<endl;
    cout<<endl;
    cout<< "                  x             f[x]"<<endl;
    for (i = 1; i<=nb; i++)
	{
        xacc = (0.000001) * (xb1[i] + xb2[i]) / 2.0;
        root = rtbis(xb1[i], xb2[i], xacc);
        cout<< setw(8)<< " root"<<i;
        cout<< setw(12)<<root;
        cout<< setw(18)<<bessj0(root)<<endl;
	}
}