// Exercise3_12.java: Approximate PI
public class Exercise3_12
{
  public static void main(String[] args)
	{
    double oldPI=4, newPI=4.0-4.0/3.0, term=0; 
		int i = 5;
		double sign = 1.0;

		//int sign = 1; what is wrong? try it find out

		while (Math.abs(newPI-oldPI) > 0.00001)
		{	oldPI = newPI;
			term = sign*4/i;
			newPI = newPI+term;
			i = i+2;
			sign = -sign;
		}
		
		System.out.println("The PI is " + newPI);
		System.out.println("The number of terms needed is " + i);	
	}
}