if Statement
| Scheme | (if expr S_1 ) | (if expr S_1 S_2 ) |
| Pascal | if expr then S_1 | if expr then S_1 else S_2 |
| C++, Java | if ( expr ) S_1 | if ( expr ) S_1 else S_2 |
| expr ? expr_1 : expr_2 |
The else part of the statement is optional. If multiple statements are to be included in the then or else part, a begin - end or { } must be used.
The operator pair ? : may be used in C++ and Java for expressions only.
| Scheme: | (set! larger (if (>= x y) x y)) |
| C++, Java: | larger = (x >= y) ? x : y |
There is a language ambiguity regarding the else part of nested if statements:
if amount > balance
then if student then bounce
else pay
Rule: The else belongs to the closest if statement.