HP 3000 Manuals HP 3000 Manuals
Unary Arithmetic Operators
A unary arithmetic operator combined with a single operand forms a unary
expression used to negate a variable, or determine the ones complement or
logical complement of the variable.
Syntax
+ cast-expression
- cast-expression
~ cast-expression
! cast-expression
Description
The unary plus operator operates on a single arithmetic operand, as is
the case of the unary minus operator. The result of the unary plus
operator is defined to be the value of its operand. For example, just as
-2 is an expression with the value negative 2, +2 is an expression with
the value positive 2.
In spite of its definition, the unary plus operator is not purely a
no-op. According to the ANSI standard, an unary plus operation is an
expression that follows the integral promotion rule. For example, if i
is defined as a short int, then sizeof (i ) is 2. However, sizeof (+i)
is 4 because the unary plus operator promotes i to an int. The result of
the unary - operator is the negative value of its operand. The operand
can be any arithmetic type. The integral promotion is performed on the
operand before it is used. The result has the promoted type and is not
an lvalue.
The result of the unary ~ operator is a one's (bitwise) complement of its
operand. The operand can be of any integral type. The integral
promotion is performed on the operand before it is used. The result has
the promoted type and is not an lvalue.
The result of the unary ! operator is the logical complement of its
operand. The operand can be of any scalar type. The result has type int
and is not an lvalue. If the operand had a zero value, the result is 1.
If the operand had a nonzero value, the result is 0.