牛顿迭代.cpp

来自「用C++实现的多个算法」· C++ 代码 · 共 38 行

#include<iostream.h>
#include<math.h>
#include<iomanip.h>
double f(double x);
double fr(double x);
void main()
{
	double x0,x1,e;
	int k=0;
	cout<<"请输入xo和e的值："<<endl;
	cout<<"x0=";
	cin>>x0;
	cout<<"e=";
	cin>>e;
	x1=x0-f(x0)/fr(x0);
	while(fabs(x1-x0)>=e)
	{
		x0=x1;
		x1=x0-f(x0)/fr(x0);
		k++;
		cout<<"x="<<x0<<endl;
		cout<<setw(15)<<setprecision(7)<<" "<<x1<<endl;
	}cout<<"迭代次数为："<<k<<endl;
}
double f(double x)
{
	double y;
	y=x*x-10;
	return y;
}

double fr(double x)
{
	double y1;
	y1=2*x;
	return y1;
}