Operator Overloading

Why overload operators?

Operators that cannot be overloaded

Operators that shouldn't be overloaded

Reasonable operators to overload

• basic arithmetic

• assignment

• bit

• relational

• unary

• shift

• others

   

   

   

Can't

• create new operators

• change precedence or associativity

• change arity

Keep in mind

• don't overload just because you can

• be aware of commutative (symmetric) operations

• be aware of what happens if operands are of different types

Conventions

(binary) arithmetic operators:

assignment operators:

relational operators:

Member vs. non-member

Member function

Non-member function

Consider:

Must be (non-static) member functions:

Use non-member if:

• operator is "symmetrical"

• want to allow implicit type conversion of left operand

• instance you would want to invoke it on is not of the class where the operator would be defined