I noticed this in some MonoTouch code that I wrote recently, but I think it makes sense across other languages as well. Let’s say you write a method that returns an incremented variable like this:
private int MyAwesomeFunction(int pVar)
{
// coding magic
return pVar++;
}
…where pVar = 10, the returned value will NOT be 11! The returned value will still be 10. If you want to return an incremented value for pVar, do the following:
private int MyAwesomeFunction(int pVar)
{
// coding magic
return ++pVar; // or return pVar+1;
}
Just a case of postfix vs prefix. In the previous example, the variable never gets incremented because the postfix operator would get evaluated after the line is processed, but that never happens because we’re returning the pVar. By flipping to a prefix operator, we guarantee that we evaluate the opperator against the variable before we return it.
It’s also worth mentioning that being a little verbose here is also good. Explicitly stating that you’re adding 1 to the variable (as displayed in the commented code) is the same number of characters and we eliminate the confusion over what’s getting returned.
Happy Coding!
I’d go with pVar + 1. The intent is clearer; when you use the increment operator, the intent is usually to change a variable’s value, but in this case you’re just returning and not using the variable’s value at all.
I think you’ve just supported Matz’s case for leaving the increment operator out of Ruby.