Collatz Conjecture

Mission:

Create a function that takes any whole number n greater than 0. If n is even, halve it, else multiply it by three then add one. Continue the process until it becomes 1.

Example:

collatz(7);

output:

7
22
11
34
17
52
26
13
40
20
10
5
16
8
4
2
1

Solution:

/*****
 *
 *	string collatz(int $input)
 *
 *	Return a string of the calculating process.
 *
 *****/
function collatz($input)
{
 	$result = $input;
 
  	if($result != 1)
 	{
		echo $result . "\n";
 
	 	if($result % 2 == 0)
		{
		 	$result /= 2;
		}
		else if($result % 2 == 1)
		{
		 	$result = $result * 3 + 1;
		}
 
		($result == 1) ? print($result . "\n") : collatz($result);
	}
	else
	{
	 	echo "It's already done!";
	}
}

Demo:

http://code.imspiration.net/collatzConjecture

Download:

currently not available

Code