CalcPI2Threads.java

// CalcPI2.java
class CalcPI2Threads
{
    public static void main (String [] args)
    {
        MyThread mt = new MyThread ();
        mt.start ();
        //         try
        //         {
        //             mt.join();//waits for mt to terminate before the next line of code is exechuted.
        //         }
        //         catch (InterruptedException e)
        //         {
        //         }
        System.out.println ("pi = " + mt.pi);
    }
}
class MyThread extends Thread
{
    boolean negative = true;
    double pi; // Initializes to 0.0, by default
    public void run ()
    {
        for (int i = 3; i < 100000; i += 2)
        {
            if (negative)
                pi -= (1.0 / i);
            else
                pi += (1.0 / i);
            negative = !negative;
        }
        pi += 1.0;
        pi *= 4.0;
        System.out.println ("Finished calculating PI");
    }
}