c++实现复合求积公式 和辛普森公式

//复合梯形和辛普森公式的算法实现
#include<iostream>
#include<cmath>
using namespace std;
class formula{
public:
	formula(double a,double b,int n);
	double function(double x);
	double Trapezoid();
	double Simpson();
private:
	double a;
	double b;
	int n;
};
formula::formula(double a,double b,int n){
	this->a=a;
	this->b=b;
	this->n=n;
}
double formula::function(double x) {
	return pow(2.71828182845904523, x);
}
//复合梯形公式
double formula::Trapezoid(){
	double h = (a - b) / n;
	double T, temp = 0;
	for (int i = 1; i <= n - 1; i++){
		double x = b + i * h;
		temp += function(x);
	}
	T = (h / 2) * (function(a) + 2 * temp + function(b));
	return T;
}
//复合Simpson积分公式
double formula::Simpson(){
	int m = n / 2;
	int i;
	double h = (a - b) / n;
	double S = 0;
	for (i = 1; i <= m - 1; i++){
		double x = b + 2 * i * h;
		S += function(x);
	}
	double temp = 0;
	for (i = 1; i <= m; i++){
		double x = b + (2 * i - 1) * h;
		temp = temp + function(x);
	}
	S = (h / 3) * (function(a) + 2 * S + 4 * temp + function(b));
	return S;
}
int main(){
	int n;
	double a, b;
	cout << "请输入区间等分的个数:" << endl;
	cin >> n;
	cout << "请输入积分上限a:\n";
	cin >> a;
	cout << "请输入积分下限b:\n";
	cin >> b;
	formula form(a,b,n);
	double T = form.Trapezoid();
	double S = form.Simpson();
	cout << "求得积分上限为" << a << "，积分下限为" << b << "的关于e^x的积分值为:" <<endl;
	cout << "梯形公式求得:" << T << endl;
	cout << "复合Simpson积分公式得:" << S << endl;
	system("pause");
	return 0;
}