5.6.2

Binary Numeric Promotion

CONVERSIONS AND PROMOTIONS

5.6.2   Binary Numeric Promotion

When an operator applies

binary numeric promotion

 to a pair of operands, each of

which must denote a value of a numeric type, the following rules apply, in order,

using widening conversion ( 5.1.2) to convert operands as necessary:

If either operand is of type

double

, the other is converted to

double

.

Otherwise, if either operand is of type

float

, the other is converted to

float

.

Otherwise, if either operand is of type

long

, the other is converted to

long

.

Otherwise, both operands are converted to type

int

.

Binary numeric promotion is performed on the operands of certain operators:

The multiplicative operators

*

,

/

 and

%

 ( 15.16)

The addition and subtraction operators for numeric types

+

 and

( 15.17.2)

The numerical comparison operators

<

,

<=

,

>

, and

>=

 ( 15.19.1)

The numerical equality operators

==

 and

!=

 ( 15.20.1)

The integer bitwise operators

&

,

^

, and

|

 ( 15.21.1)

In certain cases, the conditional operator

? :

 ( 15.24)

An example of binary numeric promotion appears above in  5.1. Here is another:

class Test {

public static void main(String[] args) {

int i = 0;

float f = 1.0f;

double d = 2.0;

//

First

i*f

 promoted to

float*float

, then

// float==double

 is promoted to

double==double

:

if (i * f == d)

System.out.println("oops");

//

A

char&byte

 is promoted to

int&int

:

byte b = 0x1f;

char c =  G ;

int control = c & b;

System.out.println(Integer.toHexString(control));

//

A

int:float

 promoted to

float:float

:

f = (b==0) ? f : 4.0f;

System.out.println(1.0/f);

}

}

74