How is the expression x---y parsed? Is it a legal expression?

Question

How is the expression x---y parsed? Is it a legal expression?

Answer 1

This is related to operator precedence. Have a look at this table.

The decrement/increment operator has precedence over the arithmetic operations. It will be parsed as x-- - y.

To correct my answer: The parser matches the longest token first, so -- is chosen over the arithmetic -. Resulting in the expression being parsed as x-- - y

Answer 2

It's legal and parsed as x-- - y.

I believe the first two minus signs are interpreted as a post-decrement operator because it's the longest token following x that is legal to appear. This leaves the third minus to play the role of subtraction. This is in accordance with the Maximal Much Rule[1]

[1]. http://en.wikipedia.org/wiki/Maximal_munch

Answer 3

(x--)-y; Which compiler do you use? What are the types of x and y?

Answer 4

For all data types, it's parsed as x-- - y. If it's some class object then you have to define post decrement operator and minus operator, it will give compiler error if you just define pre decrement operator. That means, x-- - y is forced in any case.