The prefix increment or decrement operator increments or decrements
its operand before using its value.
Description |
 |
The operand for the prefix increment ++
or the prefix decrement --
operator must be a modifiable lvalue with scalar type. The result
is not an lvalue.
The operand of the prefix increment operator is incremented
by 1. The resulting value is the result of the unary-expression.
The prefix decrement operator behaves the same way as the
prefix increment operator except that a value of one is subtracted
from the operand.
For any expression E, the unary expressions ++E
and (E+=1) yield
the same result. If the value of X
is 2, after the expression A=++X
is evaluated, A
is 3 and X is
3.
Pointers are assumed to point into arrays. Incrementing (or
decrementing) a pointer causes the pointer to point to the next
(or previous) element. This means, for example, that incrementing
a pointer to a structure causes the pointer to point to the next
structure, not the next byte within the structure.
(Refer also to "Additive Operators" for information on adding to
pointers.)
