5 Expressions [expr]

5.2 Postfix expressions [expr.post]

5.2.6 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 or a pointer to a complete object type. The value of the operand object is modified by adding 1 to it, unless the object is of type bool, in which case it is set to true. [ Note: this use is deprecated, see Annex [depr].  — end note ] 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. See also [expr.add] and [expr.ass].

The operand of postfix -- is decremented analogously to the postfix ++ operator, except that the operand shall not be of type bool. [ Note: For prefix increment and decrement, see [expr.pre.incr].  — end note ]