TimingStuff

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// TimingStuff.java
//
//Charles Cusack
//
// A simple example of how you can time things in Java
//
import java.io.PrintStream;
import java.util.Date;

public class TimingStuff
{
    // Just a simple class variable.
    int x;

    public TimingStuff()
    {
    }

    // How to time using one trial
    public void timeOneTrial()
    {
        // Get start time
        Date start = new Date();

        // Do the work you want to time
        blah();

        // Get the end time
        Date end = new Date();

        // Compute and print the elapsed time
        long time = end.getTime() - start.getTime();
        System.out.println("It took "+time+" milliseconds");
    }
    
    // How to time using several trials---for added accuracy.
    public void timeSeveralTrials(int numberTrials)
    {
        // Get the start time
        Date start = new Date();

        // Run several trials
        for(int i = 0; i < numberTrials; i++)
            blah();

        // Get the end time
        Date end = new Date();

        // Get the elapsed time and divide by number of trials.
        double time = (end.getTime() - start.getTime()*1.0)/numberTrials;

        // Printf is a nifty way to format output in Java.
        // I had a lengthy description of it, but then lost this 
        // source code and had to decompile it, and now I am too
        // lazy to put in more information.  So sue me.
        // Anyway, google "java printf" for more info.
        // Or go to Wikipedia--if it's on Wikipedia, you know it's true.
        System.out.printf("It took %7.2f milliseconds", time);
    }

    // Another way to time multiple trials.
    // The first method is probably better since if each
    // time is too small, it may register as 0 each time,
    // so the accumulated time might be too small.
    public void timeSeveralTrialsB(int numberTrials)
    {
        long totalTime = 0;
        for(int i = 0; i < numberTrials; i++)
        {
            Date start = new Date();
            blah();
            Date end = new Date();
            totalTime += end.getTime() - start.getTime();
        }

        double time = totalTime*1.0/numberTrials;
        System.out.printf("It took %7.2f milliseconds", time);
    }

    // Just a sample method to test 
    public void blah()
    {
        for(int i = 0; i < 100000; i++)
        {
            for(int j = 0; j < 10000; j++)
                x++;

        }

        System.out.println(x);
    }
}