8 Expressions [expr]

8.2 Postfix expressions [expr.post]

8.2.6 Increment and decrement [expr.post.incr]

The value of a postfix ++ expression is the value of its operand. [Note: The value obtained is a copy of the original value end note] The operand shall be a modifiable lvalue. The type of the operand shall be an arithmetic type other than cv bool, or a pointer to a complete object type. The value of the operand object is modified by adding 1 to it. The value computation of the ++ expression is sequenced before the modification of the operand object. With respect to an indeterminately-sequenced function call, the operation of postfix ++ is a single evaluation. [Note: Therefore, a function call shall not intervene between the lvalue-to-rvalue conversion and the side effect associated with any single postfix ++ operator. end note] The result is a prvalue. The type of the result is the cv-unqualified version of the type of the operand. If the operand is a bit-field that cannot represent the incremented value, the resulting value of the bit-field is implementation-defined. See also [expr.add] and [expr.ass].

The operand of postfix -- is decremented analogously to the postfix ++ operator. [Note: For prefix increment and decrement, see [expr.pre.incr]. end note]