Question

Does this condition:

if (x > 1)
//some logic
else if (y >47)
//some logic
else
//default logic

Does this always translate to :

if (x >1)
{some logic}
else{
  if (y >47)
    {some logic}
    else
    {default logic}
}

Or are there exceptions? If no exceptions, then is there a best practice of how to write this?

Answer 1

These forms are logically equivalent, yes. I think the best practise is to write the code so it is as easy to understand as possible.

Consider:

if (A) { // code #1 }
else if (B) { // code #2 }
else { // code #3 }

The truth table is then

A B code
T T #1    *
T F #1    *
F T #2
F F #3

Which is the same as for

if (A) { // code #1 }
else {
    if (B) { // code #2 }
    else { // code #3 }
}

* NB: Most languages will short-circuit these cases and not evaluate B at all, but some do. This doesn’t affect the logic though.