#include <iostream.h>
#include <math.h>
// the function we want to integrate
float f (float x)
{ 
	return (1.0/x);               
}
// Integration using trapezoid rule
float trapez (int n, float min, float max)
{
   int i;				
   float interval, sum, x;		 

   interval = (max-min) / n;
   sum=0;
   for (i=1; i<n; i++)       	// sum the midpoints
   {
      x    = min + interval * i;      
      sum = sum + f(x)*interval;
   }
   sum += 0.5 *(f(min) + f(max)) * interval;  // add the endpoints 

   return sum;
} 

void main()
{
	cout<<trapez (4, 1,2)<<endl;
}