What is a practical difference between a loop and recursion

Question

I am currently working in PHP, so this example will be in PHP, but the question applies to multiple languages.

I am working on this project with a fiend of mine, and as

Answer 1

Well, I don't know about PHP but most languages generate a function call (at the machine level) for every recursion. So they have the potential to use a lot of stack space, unless the compiler produces tail-call optimizations (if your code allows it). Loops are more 'efficient' in that sense because they don't grow the stack. Recursion has the advantage of being able to express some tasks more naturally though.

In this specific case, from a conceptual (rather than implementative) point of view, the two solutions are totally equivalent.