Lecture 8: Operator Overloading

Definition of Operator Overloading

Up to this point in the discussion of C++, the programmer could define operations on structure instance and class objects by using a function. For example:

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 c = add(a,b); 

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where a, b and c are instances of some structure or a class. However, this is using non-standard operators. C++ permits the programmer to use some of the standard operators in a more natural way using what is called: operator overloading. However, to do this requires that the programmer observe some restrictions.

To define operator overloading on class objects requires that the operator:

  • is a system operator.

  • maintains the system order of precedence

  • can not change type: i.e. between unary and binary operators

  • has at least one operand that is a class object.

  • is non static.

  • has in the operator's definition the keyword: operator

In addition, the programmer should take care how the operators are defined and that the operators should model their real world use. The permissible operators for overloading are:

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While most of the C++ operators can be overloaded, the dot operator (.) and some other operators can not be overloaded. The discussion in this lecture will only cover a few of the operators above.

Intermediate Business Programming with C++
Intermediate Business Programming with C++
ISBN: 738453099
Year: 2007
Pages: 142

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