5.1.3

Narrowing Primitive Conversions

CONVERSIONS AND PROMOTIONS

sent type

T

. In addition to a possible loss of information about the magnitude of

the numeric value, this may cause the sign of the resulting value to differ from the

sign of the input value.

A narrowing conversion of a character to an integral type

T

 likewise simply

discards all but the

n

lowest order bits, where

n

is the number of bits used to rep 

resent type

T

. In addition to a possible loss of information about the magnitude of

the numeric value, this may cause the resulting value to be a negative number,

even though characters represent 16 bit unsigned integer values.

A narrowing conversion of a floating point number to an integral type

T

 takes

two steps:

1. In the first step, the floating point number is converted either to a

long

, if

T

 is

long

, or to an

int

, if

T

 is

byte

,

short

,

char

, or

int

, as follows:

N

If the floating point number is NaN ( 4.2.3), the result of the first step of the

conversion is an

int

 or

long 0

.

N

Otherwise, if the floating point number is not an infinity, the floating point

value is rounded to an integer value

V

, rounding toward zero using IEEE

754 round toward zero mode ( 4.2.3). Then there are two cases:

O

If

T

 is

long

, and this integer value can be represented as a

long

, then the

result of the first step is the

long

 value

V

.

O

Otherwise, if this integer value can be represented as an

int

, then the

result of the first step is the

int

 value

V

.

N

Otherwise, one of the following two cases must be true:

O

The value must be too small (a negative value of large magnitude or nega 

tive infinity), and the result of the first step is the smallest representable

value of type

int

 or

long

.

O

The value must be too large (a positive value of large magnitude or posi 

tive infinity), and the result of the first step is the largest representable

value of type

int

 or

long

.

2. In the second step:

N

If

T

 is

int

 or

long

, the result of the conversion is the result of the first step.

N

If

T

 is

byte

,

char

, or

short

, the result of the conversion is the result of a

narrowing conversion to type

T

 ( 5.1.3) of the result of the first step.

56