11 Friends, Overloaded Operators, and Arrays in Classes

1. 11.1 Friend Functions 622

   1. Programming Example: An Equality Function 622

   2. Friend Functions 626

   3. Programming Tip: Define Both Accessor Functions and Friend Functions 628

   4. Programming Tip: Use Both Member and Nonmember Functions 630

   5. Programming Example: Money Class (Version 1) 630

   6. Implementation of digitToInt (Optional) 637

   7. Pitfall: Leading Zeros in Number Constants 638

   8. The const Parameter Modifier 640

   9. Pitfall: Inconsistent Use of const 641

2. 11.2 Overloading Operators 645

   1. Overloading Operators 646

   2. Constructors for Automatic Type Conversion 649

   3. Overloading Unary Operators 651

   4. Overloading >> and << 652

3. 11.3 Arrays and Classes 662

   1. Arrays of Classes 662

   2. Arrays as Class Members 666

   3. Programming Example: A Class for a Partially Filled Array 667

4. 11.4 Classes and Dynamic Arrays 669

   1. Programming Example: A String Variable Class 670

   2. Destructors 673

   3. Pitfall: Pointers as Call-by-Value Parameters 676

   4. Copy Constructors 677

   5. Overloading the Assignment Operator 682

1. Chapter Summary 685

2. Answers to Self-Test Exercises 685

3. Practice Programs 695

4. Programming Projects 696

Give us the tools, and we’ll finish the job.

WINSTON CHURCHILL, Radio Broadcast, February 9, 1941

Introduction

This chapter teaches you more techniques for defining functions and operators for classes, including overloading common operators such as +, *, and / so that they can be used with the classes you define in the same way that they are used with the predefined types such as int and double.

Prerequisites

This chapter uses material from Chapters 2 through 10.