- •Table of Contents
- •Introduction
- •What Is C++?
- •Conventions Used in This Book
- •How This Book Is Organized
- •Part I: Introduction to C++ Programming
- •Part III: Introduction to Classes
- •Part IV: Inheritance
- •Part V: Optional Features
- •Part VI: The Part of Tens
- •Icons Used in This Book
- •Where to Go from Here
- •Grasping C++ Concepts
- •How do I program?
- •Installing Dev-C++
- •Setting the options
- •Creating Your First C++ Program
- •Entering the C++ code
- •Building your program
- •Executing Your Program
- •Dev-C++ is not Windows
- •Dev-C++ help
- •Reviewing the Annotated Program
- •Examining the framework for all C++ programs
- •Clarifying source code with comments
- •Basing programs on C++ statements
- •Writing declarations
- •Generating output
- •Calculating Expressions
- •Storing the results of expression
- •Declaring Variables
- •Declaring Different Types of Variables
- •Reviewing the limitations of integers in C++
- •Solving the truncation problem
- •Looking at the limits of floating-point numbers
- •Declaring Variable Types
- •Types of constants
- •Special characters
- •Are These Calculations Really Logical?
- •Mixed Mode Expressions
- •Performing Simple Binary Arithmetic
- •Decomposing Expressions
- •Determining the Order of Operations
- •Performing Unary Operations
- •Using Assignment Operators
- •Why Mess with Logical Operations?
- •Using the Simple Logical Operators
- •Storing logical values
- •Using logical int variables
- •Be careful performing logical operations on floating-point variables
- •Expressing Binary Numbers
- •The decimal number system
- •Other number systems
- •The binary number system
- •Performing Bitwise Logical Operations
- •The single bit operators
- •Using the bitwise operators
- •A simple test
- •Do something logical with logical calculations
- •Controlling Program Flow with the Branch Commands
- •Executing Loops in a Program
- •Looping while a condition is true
- •Using the for loop
- •Avoiding the dreaded infinite loop
- •Applying special loop controls
- •Nesting Control Commands
- •Switching to a Different Subject?
- •Writing and Using a Function
- •Divide and conquer
- •Understanding the Details of Functions
- •Understanding simple functions
- •Understanding functions with arguments
- •Overloading Function Names
- •Defining Function Prototypes
- •Variable Storage Types
- •Including Include Files
- •Considering the Need for Arrays
- •Using an array
- •Initializing an array
- •Accessing too far into an array
- •Using arrays
- •Defining and using arrays of arrays
- •Using Arrays of Characters
- •Creating an array of characters
- •Creating a string of characters
- •Manipulating Strings with Character
- •String-ing Along Variables
- •Variable Size
- •Address Operators
- •Using Pointer Variables
- •Comparing pointers and houses
- •Using different types of pointers
- •Passing Pointers to Functions
- •Passing by value
- •Passing pointer values
- •Passing by reference
- •Limiting scope
- •Examining the scope problem
- •Providing a solution using the heap
- •Defining Operations on Pointer Variables
- •Re-examining arrays in light of pointer variables
- •Applying operators to the address of an array
- •Expanding pointer operations to a string
- •Justifying pointer-based string manipulation
- •Applying operators to pointer types other than char
- •Contrasting a pointer with an array
- •Declaring and Using Arrays of Pointers
- •Utilizing arrays of character strings
- •Identifying Types of Errors
- •Choosing the WRITE Technique for the Problem
- •Catching bug #1
- •Catching bug #2
- •Calling for the Debugger
- •Defining the debugger
- •Finding commonalities among us
- •Running a test program
- •Single-stepping through a program
- •Abstracting Microwave Ovens
- •Preparing functional nachos
- •Preparing object-oriented nachos
- •Classifying Microwave Ovens
- •Why Classify?
- •Introducing the Class
- •The Format of a Class
- •Accessing the Members of a Class
- •Activating Our Objects
- •Simulating real-world objects
- •Why bother with member functions?
- •Adding a Member Function
- •Creating a member function
- •Naming class members
- •Calling a Member Function
- •Accessing a member function
- •Accessing other members from a member function
- •Defining a Member Function in the Class
- •Keeping a Member Function After Class
- •Overloading Member Functions
- •Defining Arrays of and Pointers to Simple Things
- •Declaring Arrays of Objects
- •Declaring Pointers to Objects
- •Dereferencing an object pointer
- •Pointing toward arrow pointers
- •Passing Objects to Functions
- •Calling a function with an object value
- •Calling a function with an object pointer
- •Calling a function by using the reference operator
- •Returning to the Heap
- •Comparing Pointers to References
- •Linking Up with Linked Lists
- •Performing other operations on a linked list
- •Hooking up with a LinkedListData program
- •A Ray of Hope: A List of Containers Linked to the C++ Library
- •Protecting Members
- •Why you need protected members
- •Discovering how protected members work
- •Protecting the internal state of the class
- •Using a class with a limited interface
- •Creating Objects
- •Using Constructors
- •Why you need constructors
- •Making constructors work
- •Dissecting a Destructor
- •Why you need the destructor
- •Working with destructors
- •Outfitting Constructors with Arguments
- •Justifying constructors
- •Using a constructor
- •Defaulting Default Constructors
- •Constructing Class Members
- •Constructing a complex data member
- •Constructing a constant data member
- •Constructing the Order of Construction
- •Local objects construct in order
- •Static objects construct only once
- •Global objects construct in no particular order
- •Members construct in the order in which they are declared
- •Destructors destruct in the reverse order of the constructors
- •Copying an Object
- •Why you need the copy constructor
- •Using the copy constructor
- •The Automatic Copy Constructor
- •Creating Shallow Copies versus Deep Copies
- •Avoiding temporaries, permanently
- •Defining a Static Member
- •Why you need static members
- •Using static members
- •Referencing static data members
- •Uses for static data members
- •Declaring Static Member Functions
- •What Is This About, Anyway?
- •Do I Need My Inheritance?
- •How Does a Class Inherit?
- •Using a subclass
- •Constructing a subclass
- •Destructing a subclass
- •Having a HAS_A Relationship
- •Why You Need Polymorphism
- •How Polymorphism Works
- •When Is a Virtual Function Not?
- •Considering Virtual Considerations
- •Factoring
- •Implementing Abstract Classes
- •Describing the abstract class concept
- •Making an honest class out of an abstract class
- •Passing abstract classes
- •Factoring C++ Source Code
- •Defining a namespace
- •Implementing Student
- •Implementing an application
- •Project file
- •Creating a project file under Dev-C++
- •Comparing Operators with Functions
- •Inserting a New Operator
- •Overloading the Assignment Operator
- •Protecting the Escape Hatch
- •How Stream I/O Works
- •The fstream Subclasses
- •Reading Directly from a Stream
- •Using the strstream Subclasses
- •Manipulating Manipulators
- •Justifying a New Error Mechanism?
- •Examining the Exception Mechanism
- •What Kinds of Things Can I Throw?
- •Adding Virtual Inheritance
- •Voicing a Contrary Opinion
- •Generalizing a Function into a Template
- •Template Classes
- •Do I Really Need Template Classes?
- •Tips for Using Templates
- •The string Container
- •The list Containers
- •Iterators
- •Using Maps
- •Enabling All Warnings and Error Messages
- •Insisting on Clean Compiles
- •Limiting the Visibility
- •Avoid Overloading Operators
- •Heap Handling
- •Using Exceptions to Handle Errors
- •Avoiding Multiple Inheritance
- •Customize Editor Settings to Your Taste
- •Highlight Matching Braces/Parentheses
- •Enable Exception Handling
- •Include Debugging Information (Sometimes)
- •Create a Project File
- •Customize the Help Menu
- •Reset Breakpoints after Editing the File
- •Avoid Illegal Filenames
- •Include #include Files in Your Project
- •Executing the Profiler
- •System Requirements
- •Using the CD with Microsoft Windows
- •Using the CD with Linux
- •Development tools
- •Program source code
- •Index
36 |
Part I: Introduction to C++ Programming |
Are These Calculations Really Logical?
C++ provides a logical variable called bool. The type bool comes from Boolean, the last name of the inventor of the logical calculus. There are two values for a boolean variable: true and false.
There are actually calculations that result in the value bool. For example, “x is equal to y” is either true or false.
Mixed Mode Expressions
C++ allows you to mix variable types in a single expression. That is, you are allowed to add an integer with a double precision floating-point value. In the following expression, for example, nValue1 is allowed to be an int:
//in the following expression the value of nValue1
//is converted into a double before performing the
//assignment
int nValue1 = 1; nValue1 + 1.0;
An expression in which the two operands are not the same type is called a mixed-mode expression. Mixed-mode expressions generate a value whose type is equal to the more capable of the two operands. In this case, nValue1 is con verted to a double before the calculation proceeds. Similarly, an expression of one type may be assigned to a variable of a different type, as in the following statement:
//in the following assignment, the whole
//number part of fVariable is stored into nVariable double dVariable = 1.0;
int nVariable; nVariable = dVariable;
You can lose precision or range if the variable on the left side of the assignment is smaller. In the previous example, C++ truncates the value of dVariable before storing it in nVariable.
Converting a larger value type into a smaller value type is called demotion, whereas converting values in the opposite direction is known as promotion. Programmers say that the value of int variable nVariable1 is promoted to a double as expressions such as the following:
int nVariable1 = 1;
double dVariable = nVariable1;
Chapter 2: Declaring Variables Constantly |
37 |
Naming conventions
You may have noticed that the name of each variable begins with a special character that seems to have nothing to do with the name. These special characters are shown in the fol lowing table. You can immediately recognize dVariable as a variable of type double by using this convention.
Character |
Type |
n |
int |
l |
long |
f |
float |
d |
double |
c |
character |
sz |
string |
These leading characters help the programmer keep track of the variable type. Thus, you can immediately identify the following as a mixedmode assignment of a long variable to an int variable:
nVariable = lVariable;
These leading characters have no significance to C++. You don’t need to adopt any naming scheme at all if you don’t want to. Here’s what you get:
double myVariable; int someIntValue;
double nThisDoesntEvenMatch;
I used this first-letter-naming convention in this chapter to simplify the discussion; many pro grammers use this naming scheme all the time.
Mixed-mode expressions are not a good idea. Avoid forcing C++ to do your conversions for you.
38 |
Part I: Introduction to C++ Programming |
Chapter 3
Performing Mathematical
Operations
In This Chapter
Defining mathematical operators in C++
Using the C++ mathematical operators
Identifying expressions
Increasing clarity with special mathematical operators
Amathematician uses more than just the variables described in Chap ter 2. A mathematician must do something with those variables: She can
add them together, subtract them, multiply them, and perform an almost end less list of other operations.
C++ offers the same set of basic operations: C++ programs can multiply, add, divide, and so forth. Programs have to be able to perform these operations in order to get anything done. What good is an insurance program if it can’t cal culate how much you’re supposed to (over) pay?
C++ operations look like the arithmetic operations you would perform on a piece of paper, except you have to declare any variables before you can use them (as detailed in Chapter 2):
int var1; int var2 = 1;
var1 = 2 * var2;
Two variables, var1 and var2, are declared. var2 is initialized to 1. var1 is assigned the value resulting from the calculation two times the value of var2.
This chapter describes the complete set of C++ mathematical operators.