C++ For Dummies®, 6th Edition

Chapter 22. A New Assignment Operator, Should You Decide to Accept It

In This Chapter

• Introducing the assignment operator

• Knowing why and when the assignment operator is necessary

• Understanding similarities between the assignment operator and the copy constructor

The intrinsic data types are built into the language, such as int, float, and double and the various pointer types. Chapters 3 and 4 describe the operators that C++ defines for the intrinsic data types. C++ enables the programmer to define the operators for classes that the programmer has created in addition to these intrinsic operators. This is called operator overloading.

Normally, operator overloading is optional and not attempted by beginning C++ programmers. A lot of experienced C++ programmers (including me) don't think operator overloading is such a great idea either. However, you must figure out how to overload one operator: the assignment operator.

Comparing Operators with Functions

An operator is nothing more than a built-in function with a peculiar syntax. The following addition operation

a + b

could be understood as though it were written

operator+(a, b)

In fact, C++ gives each operator a function-style name. The functional name of an operator is the operator symbol preceded by the keyword operator and followed by the appropriate argument types. For example, the + operator that adds an int to an int generating an int is called int operator+ (int, int).

Any existing operator can be defined for a user-defined class. Thus, ...