For an operation of the form x * y, binary operator overload resolution (?4.
2.4) is applied to select a
specific operator implementation. The operands are converted to the
parameter types of the selected
operator, and the type of the result is the return type of the operator.
The predefined multiplication operators are listed below. The operators all
compute the product of x and y.
?Integer multiplication:
int operator *(int x, int y);
uint operator *(uint x, uint y);
long operator *(long x, long y);
ulong operator *(ulong x, ulong y);
In a checked context, if the product is outside the range of the result
type, a
System.OverflowException is thrown. In an unchecked context, overflows are
not reported and
any significant high-order bits outside the range of the result type are
discarded.
?Floating-point multiplication:
float operator *(float x, float y);
double operator *(double x, double y);
Chapter 14 Expressions
157
The product is computed according to the rules of IEC 60559 arithmetic. The
following table lists the
results of all possible combinations of nonzero finite values, zeros,
infinities, and NaN?s. In the table, x
and y are positive finite values. z is the result of x * y. If the result
is too large for the destination type,
z is infinity. If the result is too small for the destination type, z is
zero.
+y -y +0 -0 +8 -8 NaN
+x +z -z +0 -0 +8 -8 NaN
-x -z +z -0 +0 -8 +8 NaN
+0 +0 -0 +0 -0 NaN NaN NaN
-0 -0 +0 -0 +0 NaN NaN NaN
+8 +8 -8 NaN NaN +8 -8 NaN
-8 -8 +8 NaN NaN -8 +8 NaN
NaN NaN NaN NaN NaN NaN NaN NaN
?Decimal multiplication:
decimal operator *(decimal x, decimal y);
If the resulting value is too large to represent in the decimal format, a
System.OverflowException
is thrown. If the result value is too small to represent in the decimal
format, the result is zero. The scale
of the result, before any rounding, is the sum of the scales of the two
operands.
Decimal multiplication is equivalent to using the multiplication operator
of type System.Decimal.