Is there any appreciable difference between if and if-else?

Question

Given the following code snippets, is there any appreciable difference?

public boolean foo(int input) {
   if(input > 10) {
       doStuff();
       retur         


        

Answer 1

Use whatever form best describes your intent.

Do not follow the single exit principle if things are this simple, though--it just makes it more confusing.

Answer 2

Think of this case when the two examples won't be similar:

    public boolean foo(int input) {
        if (input > 10) {
            // doStuff();
            return true;
        }
        System.out.println("do some other intermediary stuff");
        if (input == 0) {
            // doOtherStuff();
            return true;
        }

        return false;
    }

vs.

    public boolean foo(int input) {
        if (input > 10) {
            // doStuff();
            return true;
        } 
        //System.out.println("doing some intermediary stuff... doesn't work");
        else if (input == 0) {
            // doOtherStuff();
            return true;
        } else {
            return false;
        }
        return false;
    }

The first approach is probably more flexible, but both formulas have their use in different circumstances.

Regarding performance, I think the differences are to small to be taken in consideration, for any regular java application, coded by sane programmers :).

Answer 3

With the second example you state very clearly that both conditions are mutually exclusive.
With the first one, it is not so clear, and in the (unlikely) event that an assignment to input is added between both ifs, the logic would change.
Suppose someone in the future adds input = 0 before the second if.
Of course this is unlikely to happen, but if we are talking about maintainability here, if-else says clearly that there are mutually exclusive conditions, while a bunch of ifs don't, and they are not so dependent between each other as are if-else blocks.

edit:Now that I see, in this particular example, the return clause forces the mutual exclusivity, but again, we're talking about maintainability and readability.

Anyway, about performance, if this is coded in Java you shouldn't care for performance of a couple of if blocks, if it were embedded C in a really slow hardware, maybe, but certainly not with java.