using currentTimeMillis for a method

Question

I'm trying to record the time elapsed to run a certain method using currentTimeMillis, but am having trouble printing out the time...

public int foo(int n, int k) {
    if(n<=k)
        return 1;
    else
        return foo(n/k,k) + 1;
}

Where would I write in the lines for starTime, endTime, and the difference?

I tried throwing it in a different method:

public static long p3(int n, int k){
    long starTime = System.currentTimeMillis();
    foo(n, k);
    long endTime = System.currentTimeMillis();
    long difference = endTime - starTime;
    return difference;
}

But the difference always appears as 0...

Answer 1

If the method takes less than a milisecond to execute then yes the difference will be zero.

Then you need to work with nanoseconds. System class has a method for these too: System#nanoTime();