數值積分之Newton_Cotes閉合積分公式

//Newton_Cotes閉合積分公式
#include <iostream>
#include <math.h>

using namespace std;

class trapezoidal
{
private:
 int n, k;
 double a, b, f, h, integral, sum;

public:
 double func(double v)
 {
  f = 24.6 / (v - 0.065) - 5.5 / pow(v, 2);
  return f;
 }
 void integration();
};

void main()
{
 trapezoidal trape;
 trape.integration();
}

void trapezoidal::integration()
{
 cout << "\n輸入下限和上限：";
 cin >> a >> b;
 cout << "\n輸入你要的段數：";
 cin >> n;
 h = (b - a) / n;
 sum = 0.0;
 for (k = 1; k < n; k++)
 {
  sum += func(a + k * h);
 }
 integral = (h / 2.0) * (func(a) + 2.0 * sum + func(b));
 cout << endl << "積分值 = " << integral << endl;
}