++ operator on a pointer to struct member

Question

I came across a piece of code that reads:

++myStruct->counter

I'm confused on how the ++ operator and -> operator are evaluated here. The ++ has precedence over the -> operator and left to right evaluation. It appears the ++ operator would actually perform pointer arithmetic on 'myStruct', not increment the counter member.

Answer 1

The ++ has precedence over the -> operator and left to right evaluation.

This is not correct - postfix operators like -> have higher precedence than unary (prefix) operators ++ and --. The expression is parsed as

++(myStruct->counter)

so the counter member of myStruct is being incremented.

Answer 2

The postfix increment and decrement have the same precedence as the -> operator and left-to-right associativity, but the prefix increment and decrement are after. So the code does increment the variable counter and not the myStruct.