import java.lang.Thread;
import java.util.Random;

public class dualsumT implements Runnable {
    int start;
    int extent;
    double bigarray[];
    double sum;

    public dualsumT( int istart, int iextent, double ibigarray[] ) {
				start = istart;
				extent = iextent;
				bigarray = ibigarray;
				sum = 0.0;
    }

    public void run() {
				int end = start + extent;
				for(int m = 0;m<1000000;m++) {
						for(int i = start;i<end;i++) {
								sum += bigarray[i];
						}
				}
    }

    public double sum() {
				return sum;
    }

    public static void main(String argv[]) {
				int size = 10;
				double ba[] = new double[ size ];
				Random gen = new Random();

				for(int i=0;i<size;i++) {
						ba[i] = gen.nextDouble();
				}

				dualsumT ds1 = new dualsumT( 0, size/2, ba );
				dualsumT ds2 = new dualsumT( size/2, size/2, ba );
				dualsumT single = new dualsumT( 0, size, ba );

				Thread t1 = new Thread( ds1 );
				Thread t2 = new Thread( ds2 );
				Thread s1 = new Thread( single );

				long start = System.currentTimeMillis();
				t1.start();
				t2.start();
				try {
						t1.join();
						t2.join();
				}
				catch(InterruptedException e ) {
						return;
				}
				long end = System.currentTimeMillis();

				double sum = ds1.sum() + ds2.sum() ;

				System.out.printf("2 thread sum %.2f in %dms\n", sum, end - start );

	
				start = System.currentTimeMillis();
				s1.start();
				try {
						s1.join();
				}
				catch(InterruptedException e ) {
						return;
				}
				end = System.currentTimeMillis();
				System.out.printf("1 thread sum %.2f in %dms\n", single.sum(), end - start );

	
    }
}