7 Expressions [expr]

7.6 Compound expressions [expr.compound]

7.6.1 Postfix expressions [expr.post]

7.6.1.6 Increment and decrement [expr.post.incr]

1
#
The value of a postfix ++ expression is the value of its operand.
[Note 1: 
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.
An operand with volatile-qualified type is deprecated; see [depr.volatile.type].
The value of the operand object is modified ([defns.access]) 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 2: 
Therefore, a function call cannot 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].
2
#
The operand of postfix -- is decremented analogously to the postfix ++ operator.
[Note 3: 
For prefix increment and decrement, see [expr.pre.incr].
— end note]