In C++, it is possible to define operators such as
-> for user-defined types. For example, the
<string> header defines a
+ operator to concatenate strings. This is done by defining an operator function using the
The operators for built-in types cannot be changed, operators can only be overloaded for user-defined types. That is, at least one of the operands has to be of a user-defined type.
The following operators cannot be overloaded:
##, which are executed before any type information is available.
There are some operators that you should not (99.98% of the time) overload:
||(prefer, instead, to use implicit conversion to
Why? Because they overload operators that another programmer might never expect, resulting in different behavior than anticipated.
For example, the user defined
|| overloads of these operators lose their short-circuit evaluation and lose their special sequencing properties (C++17), the sequencing issue also applies to
, operator overloads.