CODEWITHSUNDEEP
c
zacharoni16
zacharoni16

Reputation: 307

++ operator on a pointer to struct member

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.

Upvotes: 4

Views: 487

Answers (3)

John Bode
John Bode

Reputation: 123448

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.

Upvotes: 5

Quentin
Quentin

Reputation: 63124

According to cppreference, the prefix ++/-- operator has lower precedence thatn the -> operator. The suffix one has the same precedence, but left-to-right associativity.

Upvotes: 3

Sami Kuhmonen
Sami Kuhmonen

Reputation: 31143

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.

Upvotes: 3

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