Programming preference - use else ifs with multiple return statements? [closed]

Answer 1

It depends on a lot of things like how complex your code is. With a simple example like this, I'd put the returns on the same line as the ifs, and not use elses. The structure and behaviour is clear:

public String getTemperatureMessage(double temp)
{
    if(temp < 32) return "Freezing";
    if(temp < 60) return "Brr";
    if(temp < 80) return "Comfortable";
    return "Too hot";
}

When I have more complex code I find it useful to not break out from the nesting with returns or continue/break, but to assign to state or result variables. I will then also include {} even if the block is a single statement, mostly to keep the consistency in how the structure is represented in code, but also to slightly reduce the risk that later edits will forget to change a statement to a block.

If this example was more complex, I'd probably code it like this:

public String getTemperatureMessage(double temp) {
    String result;
    if(temp < 32) {
        result = "Freezing";
    } else {
        if(temp < 60) {
            result = "Brr";
        } else {
            if(temp < 80) {
                result = "Comfortable";
            } else {
                result = "Too hot";
            }
        }
    }
    return result;
}

Answer 2

I don't think I'd write in this way in the first place, but going along with the premise, I'm guessing that any compiler would crank out the same code whichever method you chose to write, so there is no technical reason that I can think would favour one over the other.

The argument is therefore Single or Compound statement.

I think the rule of "least surprise" should be used, which in this case would call FOR the superfluous else statements to be included.

PS. I would always send a temperature in degrees centigrade, oops, just broke your function!

Answer 3

Who uses IF/ELSE IF... when you can use a SWITCH statement?

My preference is for the single RETURN statement - multiple return statements can make debugging a pain...

Answer 4

The redundant elses make me cringe. The extra syntax and indentation makes it harder for me to read. I just got through removing a bunch of these from some code I inherited.

Most cases of redundant code are mistakes, so by implication a redundant 'else' looks like a mistake to me even if you put it there on purpose. The impression I get is of code that was originally written without embedded returns, then someone rewrote it to have the embedded returns, but they were too lazy to remove the elses.

A single if/return is easy to understand; so are 4 in a row. It's "that case is done; let's move on". A long chain of if/elses can be a pain to read; you need to read all the way to the bottom before you find out what happens. The saving grace is it allows a single return to be used -- a feature that is overrated IMO but I'll admit it does provide some value. However a long chain of if/elses combined with returns mixed in amongst the elses is the worst of both worlds -- all the disadvantages of multiple returns, and made to look like one large construct you have to get in your head all at once. Ugh.

From a theoretical perspective consider this: The zone between the return and the else is essentially unreachable code. Sure, it only contains whitespace, but the zone shouldn't even be there at all.

Finally, an example of if/return/else taken to its redundant conclusion. I've seen a few of these lately. Why in the world is there an else block? The code in the else block executes under the same conditions as the code directly after it:

...
if (temp < 35)
{
  foo.status = TOO_COLD;
  return;
}
else
{
  foo.status = TEMP_OKAY;
}
launch_the_rocket(now);
return;

Answer 5

There's no point. You're adding needless semantic and other overheads for absolutely zero benefit. When you return, you return and control is over. Pretending anything else is superfluous and just makes you look like you don't know what the return statement does.

Answer 6

public String getTemperatureMessage(double temp)
{
    String retval = null;
    if(temp < 32)
        retval = "Freezing";
    else if(temp < 60)
        retval = "Brr";
    else if(temp < 80)
        retval = "Comfortable";
    else
        retval = "Too hot";
    return retval;
}