复化辛普森公式求积分

#include<iostream>
using namespace std;
double fun(double x) 
{	
    return 4 / (1 + x * x);
}

double Simpson(double a, double b, int n) 
{	
    double h = (b - a) / n;
    double s1 = fun(a + h / 2);	
    double s2 = 0;	
    for (int i = 1; i < n; i++) 	
    {  		
        s1 += fun(a + i * h + h / 2);		
        s2 += fun(a + i * h);	
    }	
    return h * (fun(a) + 4 * s1 + 2 * s2 + fun(b)) / 6;
}

int main() 
{	
    int n = 10;  //区间等分数	
    double a = 0, b = 1;  //上下限	
    cout << "被积函数 f = 4 / (1 + x * x)" << endl;	
    cout << "区间等分数为 10" << endl;	
    cout << "积分区间为（0，1）" << endl;	
    cout << "积分值为：" << Simpson(a, b, n) << endl;	
    return 0;
}

标签：s2,return,int,积分,s1,辛普森,复化,double,fun
来源： https://blog.csdn.net/qq_43239560/article/details/101118863