复化simpson.cpp

来自「计算方法程序,包括高斯列主元法,复化simpson,标准四阶龙格库塔,Seide」· C++ 代码 · 共 26 行

#include<iostream.h>
double f(double x)
{
	return 1/(1+x*x);
}
void main(void)
{
	double h,a,b,s1,s2=0;
	int n;
	cout<<"输入a"<<endl;
	cin>>a;
	cout<<"输入b"<<endl;
	cin>>b;
	cout<<"输入n"<<endl;
	cin>>n;
	h=(b-a)/n;
	s1=f(a+h/2);
	cout<<"f(x)=1/(1+x^2)"<<endl;
	for(int k=1;k<n;k++)
	{
		s1+=f(a+k*h+h/2);
		s2+=f(a+k*h);
	}
	cout<<"S="<<(h/6)*(f(a)+4*s1+2*s2+f(b))<<endl;
}