Why ++i++ gives “L-value required error” in C? [duplicate]

Answer 1

Generally, you should not be doing this, as it obscures the code.
The reason you're getting the error is that the post-increment has precedent and thus returns an r-value, i.e. ++i++ == ++(i++) which cannot be incremented.

However, you can use (++i)++ since the pre-increment (apparently, on VS2010) returns i itself, an l-value which can be post-incremented.