Run-Time of the algorithm..

[Steve De Costa]

I've written some code/algorithm and I'm trying to check its run-time.

Any idea if there is an effective way of doing it?

The only thing I could think of was putting my algorithm between the following two lines


System.out.println(System.currentTimeMillis());
//...then the piece of code goes here...
System.out.println(System.currentTimeMillis());

[Campbell Ritchie]

You may prefer to use the System method which gets time in nanoseconds, called something like nanoTime() (look in the API for the correct spelling).

long startTime = System.nanoTimeOrSimilar();
. . .
carry out algorithm, or do nothing at all.
. . .
long runTime = System.nanoTimeOrSimilar() - startTime;
System.out.printf("My algorithm took %d.%03d microseconds.%n", runTime / 1000, runTime % 1000);

Also note how long it takes to run when there is no code between the two nanoTime calls. Note that timings vary quite a bit on successive runs, even when everything else appears unchanged.