How should I implement the multiplication by int (z * 2
) on the last line?
public static TResult Test<TResult>() where TResult : INumber<TResult>
{
TResult x = TResult.AdditiveIdentity;
TResult y = TResult.MultiplicativeIdentity;
TResult z = x * y;
TResult z2 = z * 2; // <--- this gives the CS0019 error "The operator * cannot be applied to operands of type 'TResult' and 'int'
return z2;
}
--- the suggested solution is to add an interface, but it breaks this:
IMultiplyOperators<TResult, int, TResult>
public static void Tester()
{
Test<decimal>(); // CS0315 Tye type decimal cannot be used as type parameter TResult..... there is no boxing conversion
}
For now I will inject the function myself and use:
public static TResult Test<TResult>(Func<TResult, int, TResult> mul) where TResult : INumber<TResult>
{
TResult x = TResult.AdditiveIdentity;
TResult y = TResult.MultiplicativeIdentity;
TResult z = x * y;
TResult z2 = mul(z, 2);
return z2;
}
I suggest converting
2
toTResult
and only then multiply:Here we create
TResult
instance from integer value2
, while checking2
for overflow and similar possible errors (an exception will be thrown if2
can't be converted intoTResult
: eitherOverflowException
orNotSupportedException
).Code:
Demo:
Output:
Fiddle