The postfix operators have the highest precedence (the tightest binding) in expression evaluation.

postfix-expression:
 primary-expression
 postfix-expression [ expression ]
 postfix-expression ( argument-expression-list_opt )
 postfix-expression . identifier
 postfix-expression -> identifier
 postfix-expression ++
 postfix-expression --

Operators in this precedence level are the array subscripts, function calls, structure and union members, and postfix increment and decrement operators.

C Operators