Thread: Problem with Recursive code

Hi ya folks, I''v come to this forums a few times and have found solutions to my problems, however in this instance I can not find a solution to my problem.
Here is what I have to do:

Write a Boolean recursive method called powerof3 that takes a single positive integer argument and returns true iff the integer is a perfect power of 3 such as 1, 3, 9, 27, 81, ...
For example:
if (powerof3(81))
System.out.println("81 is a power of 3.");
else
System.out.println("81 is not a power of 3.";
displays 81 is a power of 3

The problem is that if the answer is false I run in to a Stack Over Flow error. For example, if the input is 23, I run in to an error, however if the input is 81 it passes (returns true correctly).

Here is my code:

public class Main {
 
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
        int num = 243;
        boolean it3 = powerOfThree1(num);
        System.out.println(it3);
    }
 
    private static boolean powerOfThree1(int num) {
        boolean n = false;
        if (num == 1) {
            n = true;
            return true;
        }
        if (num != 1) {
           n= powerOfThree1(num / 3);
 
        }
 
        return n;
    }
}

Can any one tell me how I should go about solving this? Also, is there any other method that I can use?

One more thing: I can not use Arrays, ArrayLists,etc for this assignment.

PS: I'm more of a hardware guy (modder, OCer,etc) than a programmer and I am finding recursions to be a bit difficult to understand and follow. Any tutorials, guides,etc will be helpful.

Remember, integers automatically truncate any decimals when you divide. Use the modulus operator to see if the number is still divisible by 3 before dividing it by 3.

^ Got it thanks!

edit: Can a mod please mark this as [Solved] I can't seem to do this in my OP.