HP C/iX Reference Manual (31506-90011)

Chapter 5 67
Expressions
Prefix Increment and Decrement Operators
Prefix Increment and Decrement Operators
The prefix increment or decrement operator increments or decrements its operand before
using its value.
Syntax
unary-expression
unary-expression
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.)