gistfile1.cpp

#include<iostream>
#include<cstdlib>
#include<cmath>
#define PI acos(-1.0)
#define Rad PI / 180.0
using namespace std;
double hw1104(int n);
int main(int argc, char* argv[])
{
	int uN = 0;
	cout << "Input N value: ", cin >> uN;
	cout << hw1104(uN) << endl;
	system("PAUSE");
	return 0;
}
double hw1104(int n)
{
	int a = 0;
	double dRet = 0.0, dRet1 = 0.0, dRet2 = 0.0, x = 0.0;
	for (int i = 0; i < n; i ++)
	{
		a = i + 1, x = (double)a;
		if ( (a & 0x1) == 0x1 )
		{
			dRet1 += (cos(x * Rad) / x);
		}
		else
		{
			dRet2 += (sin(x * Rad) / x);
		}
	}
	dRet = (dRet1 - dRet2) / PI;
	return dRet;
}