HP C/iX Reference Manual (31506-90011)

Chapter 4 51

Type Conversions

Usual Arithmetic Conversions

In many expressions involving two operands, the operands are converted according to the

following rules, known as the usual arithmetic conversions. The common type resulting

from the application of these rules is also the type of the result. These rules are applied in

the sequence listed below.

1. If either operand is long double, the other operand is converted to long double.

2. If either operand is double, the other operand is converted to double.

3. If either operand is ﬂoat, the other operand is converted to ﬂoat.

4. Integral promotions are performed on both operands, and then the rules listed below

are followed.

a. If either operand is unsigned long int, the other operand is converted to unsigned

long int.

b. If one operand is long int and the other is unsigned int, both operands are converted

to unsigned long int.

c. If either operand is long int, the other operand is converted to long int.

d. If either operand is unsigned int, the other operand is converted to unsigned int.

e. Otherwise, both operands have type int.

NOTE

In non-ANSI mode, the rules are slightly different.

Rule 1: Does not apply, because long double is not supported in non-ANSI mode.

Rule 3: Does not apply, because in non-ANSI mode, whenever a ﬂoat appears in an

expression, it is immediately converted to a double.

Rule 4: The integral promotions are performed according to the unsigned

preserving rules when compiling in non-ANSI mode.