Series to calculate value of pie (C++)

Series to calculate value of pie

π (sometimes written pi) is a mathematical constant whose value is the ratio of any circle's circumference to its diameter in the Euclidean plane; this is the same value as the ratio of a circle's area to the square of its radius. It is approximately equal to 3.14159265 in decimal notation.

calculatePIE() returns the accurate value of pie upto 4 decimal places.

Code

#include "stdafx.h"

#include "iostream"

#include "conio.h"

#include "iomanip"

#include "math.h"

using namespace std;

double calculatePIE()

{

 int x=1;

 double PIE=4;

  for(double i=3;i<100000;i+=2)

  {

            PIE=PIE+(pow(-1.0,x)*(4/i));

    x++;

  }

return PIE;

}

int main()

{

       cout<<calculatePIE();cout<<endl;

       _getche();

       return 0;

}

Output

3.14157