Operator Overloading

Operators in C++ may be overloaded in the same way that functions are overloaded. In C, the + (plus) operator is "overloaded" to work for int or float values. In C++, this concept is extended to include class types.

Notes:

You may overload the following operators:

   +    -    *    /    %    ^    &    |
   ~    !    ,    =    <    >    <=   >=
   ++   --   <<   >>   ==   !=   &&   ||
   +=   -+   /=   %=   ^=   &=   |=   *=
   <<= >>= []   ()   ->   ->* new delete

Most operators may be overloaded, both binary and unary operators. The following operators may not be overloaded:

   .        direct member
   .*        direct pointer to member
   ::        scope resolution
   ? :       ternary

To overload an operator, create a function called operator@ where @ is the operator symbol you wish to overload.

Operator precedence is still in effect for overloaded operators and may not be changed.

Default arguments are not allowed in overloaded operator functions.

For an expression involving binary operators, A + B means:

A.operator+(B) if operator+() is a class member function
operator+(A,B) if operator+() is a non-class member function

An overloaded operator function may be defined as a class member function, a friend function, or even a non-friend function.

You may not overload an operator (redefine) for the built-in primitive types. In other words, if a and b are ints, then a+b will always be (int) a+b.

You may not create any new operator symbols