15.14.2

Prefix Decrement Operator

EXPRESSIONS

and the sum is stored back into the variable. Before the addition, binary numeric

promotion ( 5.6.2) is performed on the value

1

 and the value of the variable. If

necessary, the sum is narrowed by a narrowing primitive conversion ( 5.1.3) to

the type of the variable before it is stored. The value of the prefix increment

expression is the value of the variable

after

the new value is stored.

A variable that is declared

final

 cannot be incremented, because when an

access of a

final

 variable is used as an expression, the result is a value, not a

variable. Thus, it cannot be used as the operand of a prefix increment operator.

15.14.2   Prefix Decrement Operator

He must increase, but I must decrease.

 John 3:30

A unary expression preceded by a

 operator is a prefix decrement expression.

The result of the unary expression must be a variable of a numeric type, or a com 

pile time error occurs. The type of the prefix decrement expression is the type of

the variable. The result of the prefix decrement expression is not a variable, but a

value.

At run time, if evaluation of the operand expression completes abruptly, then

the prefix decrement expression completes abruptly for the same reason and no

decrementation occurs. Otherwise, the value

1

 is subtracted from the value of the

variable and the difference is stored back into the variable. Before the subtraction,

binary numeric promotion ( 5.6.2) is performed on the value

1

 and the value of

the variable. If necessary, the difference is narrowed by a narrowing primitive con 

version ( 5.1.3) to the type of the variable before it is stored. The value of the pre 

fix decrement expression is the value of the variable

after

the new value is stored.

A variable that is declared

final

 cannot be decremented, because when an

access of a

final

 variable is used as an expression, the result is a value, not a

variable. Thus, it cannot be used as the operand of a prefix decrement operator.

15.14.3   Unary Plus Operator

+

The type of the operand expression of the unary

+

 operator must be a primitive

numeric type, or a compile time error occurs. Unary numeric promotion ( 5.6.1)

is performed on the operand. The type of the unary plus expression is the pro 

moted type of the operand. The result of the unary plus expression is not a vari 

able, but a value, even if the result of the operand expression is a variable.

At run time, the value of the unary plus expression is the promoted value of

the operand.

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