#include <stdio.h>
#include <conio.h>
#include <math.h>

const double PI = 3.14156;
const double Epsilon = 0.00001;

void main()
{
	double Somme = 0;
	double Iterations = 1;
	int Signe = 1;
	int Abandon = 0;
	double d;

	clrscr();

	do
	{
		Somme = Somme + (1.0 / Iterations) * Signe;
		Signe = -Signe;
		Iterations += 2;
		d = fabs(PI - Somme*4.0) ;
	} while( fabs(PI - Somme*4.0) > Epsilon && (Abandon=kbhit()) == 0);

	printf( "Calcul aproche en %f iterations (PI=%f)\n", (float)Iterations, (float)(Somme * 4) );
	if( Abandon ) getch();
	getch();
}