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 remainder 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.
The result of the remainder operator has the same sign as the dividend (the first operand in the expression):
As a result, code that depends on the remainder operation to always return a positive result is erroneous.
Noncompliant Code Example
This noncompliant code example uses the integer
hashKey as an index into the
A negative hash key produces a negative result from the remainder operator, causing the
lookup() method to throw
This compliant solution calls the
imod() method, which always returns a positive remainder:
Incorrectly assuming a positive remainder from a remainder operation can result in erroneous code.