Лабораторное задание №2

#include <iostream>
#include <math.h>

using namespace std;
const double pi = 3.1415926;

int main()
{
   unsigned long i, n = 4;
   double a,b,x,h,S1,S2,eps,exact;
   a = 0; b = pi/3; eps = 0.001;
   S1 = 0;
   h = (b-a)/n;
   
   for (i=1;i<=n;i++)
  {
      x = a + i*h - h/2;
      S1 = S1 + sin(x)*h;
  }
  
do
{
    n = 2*n;
    h = (b-a)/n;
    S2 = 0;
    
    for (i=1;i<=n;i++)
  {
      x = a + i*h - h/2;
      S2 = S2 + sin(x)*h;
  }
  
  exact = fabs(S1-S2);
  S1=S2;
}

while(exact>eps);
cout << "S = " << S2;
return 0;
}