Question

What is the “hanging else” problem? (Is that the right name?)

Following a C++ coding standard (forgot which one) I always
use brackets (block) with control structures. So I don’t
normally have this problem (to which “if” does the last(?)
else belong), but for understanding possible problems in
foreign code it would be nice with a firm understanding of
this problem. I remember reading about it in a book about
Pascal many years ago, but I can’t find that book.

Answer 1

Which if does the else belong to?

if (a < b)
    if (c < d)
        a = b + d;
    else
        b = a + c;

(Obviously you should ignore the indentation.)

That’s the “hanging else problem”.

C/C++ gets rid of the ambiguity by having a rule that says you can’t have an-if-without-an-else as the if-body of an-if-with-an-else.