operator * method
Performs multiplication by a nullable num value.
If both are Null, Null is returned.
If only one of them is Null, a non-null value is returned.
Nullableなnum値での乗算を行います。
Implementation
num? operator *(num? other) {
if (this == null) {
return other;
}
if (other == null) {
return this;
}
return this! * other;
}