When should I use out parameters?

Question

I don\'t understand when an output parameter should be used, I personally wrap the result in a new type if I need to return more than one type, I find that a lot easier to w

Answer 1

Yes, it does make sense. Take this for example.

String strNum = "-1";
Int32 outNum;

if (Int32.TryParse(strNum, out outNum)) {
    // success
}
else {
    // fail
}

What could you return if the operation failed in a normal function with a return value? You most certainly could not return -1 to represent a fail, because then there would be no differentiation between the fail-return value and the actual value that was being parsed to begin with. This is why we return a Boolean value to see if it succeeded, and if it did then we have our "return" value safely assigned already.