Should 'if' statement always have an 'else' clause? [closed]

Answer 1

if (thereIsSomeThingToDoInTheElse)
{
    putAnElseClause();
}
else
{
    // intentionally left blank
}

Answer 2

If your code is complex enough that this becomes an issue, you should probably be rethinking your approach to the problem. Break what you're doing down into smaller simpler functions where it should be unbelievably obvious what the if statements are doing.

If you can't break it down into smaller functions, or you find yourself nesting more than one if statement inside another, Using if statements for your conditional logic are probably not a good fit. Consider switches, lookup tables (if the only difference between your conditions is the value of some constant), or decision tables instead.

If you've already done all this, then you are quibbling over something so unbelievably trivial it's hardly worth your time to argue it.

Answer 3

There are situations where using an optional syntax element when not required can improve readability or prevent future errors. A typical case are the brackets around one-sentence conditionals:

Doing

if(foo){
    bar
}

instead of

if(foo)
    bar

could eventually prevent

if(foo)
    bar
    dot

I can't really think of any language I know where omitting an unnecessary else can lead to potential errors :-?

Answer 4

"ensures that the codes has actually addressed whether the condition requires an ELSE clause"

This is no more true than requiring a catch clause in every method ensures that all possible exceptions has been properly handled.

Answer 5

Haskell's if is always ternary. So else is mandatory.

Answer 6

I tend to use "early if" statements as means of reducing the level of nested braces (or indentation in Python) like so:

if (inParam == null) {
  return;
}

if (inParam.Value < 0) {
  throw new ArgumentException(...,...);
}
// Else ... from here on my if statements are simpler since I got here.

Of course, .Net 4.0 now has code contracts, which is great! But, most languages do not have that just yet, so "early ifs" (for the lack of better term) are great precisely because they eliminate a number of else clauses and nested ifs. I do not think it is beneficial to have an else clause in high-level languages ... heck, even in assembly! The idea is: if you checked and did not jump, then the condition was false and we can carry on. Makes logical sense to me ...

EDIT: Check out this article as well to see why else clauses are not of much help: http://www.codinghorror.com/blog/2006/01/flattening-arrow-code.html