#include <iostream>
#include <cmath>
using namespace std;

double f( double x )
{
   return( x - cos(x) );
}

int main()
{
   double a, b, h, x, sum1, sum2, sum3;
   short i, n;

   a = 0.0;
   b = 2.0;
   n = 10;
 
   h = ( b - a ) / n;
   sum1 = sum2 = sum3 = 0.0;
   x = a;
   for( i = 1; i <= n; i++ )
   {
      sum1 += f( x ); 
      x += h/2;
      sum2 += f( x );
      x += h/2;
      sum3 += f( x );
   }
   cout << "Riemann sum using left endpoints: " << h * sum1 << endl;
   cout << "Riemann sum using midpoints: " << h * sum2 << endl;
   cout << "Riemann sum using right endpoints: " << h * sum3 << endl;

   return( 0 );
}