复化simponson求积.cpp

数值分析算法之复化simpson求积算法

#include <iostream.h>
#include <math.h>
double f(double x){return 2*pow(x,2)+3;}
const int n=8;
void main ()
{
	double a,b,h,s1,s2,s;
	int k,m;
	m=n/2;
	cout<<"cin a:";cin>>a;
	cout<<"cin b:";cin>>b;
	h=(b-a)/n;
	s1=s2=0;
	for(k=1;k<=m;k++)
	{
		s1=s1+f(a+(2*k-1)*h);
	}
	for(k=1;k<=m-1;k++)
	{
		s2=s2+f(a+2*k*h);
	}
	s=h*(f(a)+f(b)+4*s1+2*s2);
	cout<<"s:"<<s;
}