Sum of a series

Sum of a series
You are encouraged to solve this task according to the task description, using any language you may know.

Display the sum of a finite series for a given range.

For this task, use S(x) = 1/x^2, from 1 to 1000.

C++

#include <iostream>

double f(double x);

int main()
{
	unsigned int start = 1;
	unsigned int end = 1000;
	double sum = 0;
	
	for(	unsigned int x = start;
			x <= end;
			++x			)
	{
		sum += f(x);
	}
	
	std::cout << "Sum of f(x) from " << start << " to " << end << " is " << sum << std::endl;
	return 0;
}


double f(double x)
{
	return ( 1 / ( x * x ) );
}