EXPRESSIONS

Remainder Operator

%

15.16.3

Division of a zero by a zero results in NaN; division of zero by any other finite

value results in a signed zero. The sign is determined by the rule stated above.

Division of a nonzero finite value by a zero results in a signed infinity. The

sign is determined by the rule stated above.

In the remaining cases, where neither an infinity, nor a zero, nor NaN is

involved, the quotient is computed. If the magnitude of the quotient is too

large to represent, we say the operation overflows; the result is then an infinity

of appropriate sign. If the magnitude is too small to represent, we say the

operation underflows and the result is then a zero of appropriate sign. Other 

wise, the quotient is rounded to the nearest representable value using IEEE

754 round to nearest mode. The Java language requires support of gradual

underflow as defined by IEEE 754 ( 4.2.4).

Despite the fact that overflow, underflow, division by zero, or loss of informa 

tion may occur, evaluation of a floating point division operator

/

 never throws a

run time exception.

15.16.3   Remainder Operator

%

And on the pedestal these words appear:

 My name is Ozymandias, king of kings:

Look on my works, ye Mighty, and despair! 

Nothing beside remains.

Percy Bysshe Shelley,

Ozymandias

(1817)

The binary

%

 operator is said to yield the remainder of its operands from an

implied division; the left hand operand is the dividend and the right hand operand

is the divisor.

In C and C++, the remainder operator accepts only integral operands, but in

Java, it also accepts floating point operands.

The remainder operation for operands that are integers after binary numeric

promotion ( 5.6.2) produces a result value such that

(a/b)*b+(a%b)

 is equal to

a

. This identity holds even in the special case that the dividend is the negative

integer of largest possible magnitude for its type and the divisor is

 1

 (the remain 

der is

0

). It follows from this rule that the result of the remainder operation can be

negative only if the dividend is negative, and can be positive only if the dividend is

positive; moreover, the magnitude of the result is always less than the magnitude

of the divisor. If the value of the divisor for an integer remainder operator is

0

,

then an

ArithmeticException

 is thrown.

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