New to Java

Hi,

public static int mystery(int a, int b) {
		   if (b == 0)     
			   return 0;
		   if (b % 2 == 0) 
			   return mystery(a+a, b/2);
		   else{
			   return mystery(a+a, b/2) + a;
		   }
		}

Can someone, please help me understand why the above code calculates a*b ? I tried with pen and paper - don't get it, tried with debugger - same result. Tried with System.out.println(mystery(a,b)); just before every return statement in effort to enlighten the case and I got StackOverflowError.

Thanks in advance.


Edit: I got it why the stack overflows when I recursively call the method through System.out.println();

Edited by: blias on Apr 8, 2011 6:14 PM