C++ A Beginner's Guide 2nd Edition (2003).pdf

Module 1

C++ Fundamentals

Table of Contents

CRITICAL SKILL 1.1: A Brief History of C++ .................................................................................................... 2

CRITICAL SKILL 1.2: How C++ Relates to Java and C#.................................................................................... 5

CRITICAL SKILL 1.3: Object-Oriented Programming...................................................................................... 7

CRITICAL SKILL 1.4: A First Simple Program ................................................................................................ 10

CRITICAL SKILL 1.5: A Second Simple Program ........................................................................................... 15

CRITICAL SKILL 1.6: Using an Operator ....................................................................................................... 17

CRITICAL SKILL 1.7: Reading Input from the Keyboard ............................................................................... 19

Project 1-1 Converting Feet to Meters ....................................................................................................... 24

CRITICAL SKILL 1.8: Two Control Statements.............................................................................................. 26

CRITICAL SKILL 1.9: Using Blocks of Code ................................................................................................... 30

Project 1-2 Generating a Table of Feet to Meter Conversions ................................................................... 33

CRITICAL SKILL 1.10: Introducing Functions................................................................................................ 35

CRITICAL SKILL 1.11: The C++ Keywords ..................................................................................................... 38

CRITICAL SKILL 1.12: Identifiers................................................................................................................... 39

If there is one language that defines the essence of programming today, it is C++. It is the preeminent

language for the development of high-performance software. Its syntax has become the standard for

professional programming languages, and its design philosophy reverberates throughout computing.

C++ A Beginner’s Guide by Herbert Schildt

C++ is also the language from which both Java and C# are derived. Simply stated, to be a professional

programmer implies competency in C++. It is the gateway to all of modern programming.

The purpose of this module is to introduce C++, including its history, its design philosophy, and several

of its most important features. By far, the hardest thing about learning a programming language is the

fact that no element exists in isolation. Instead, the components of the language work together. This

interrelatedness makes it difficult to discuss one aspect of C++ without involving others. To help

overcome this problem, this module provides a brief overview of several C++ features, including the

general form of a C++ program, some basic control statements, and operators. It does not go into too

many details, but rather concentrates on the general concepts common to any C++ program.

CRITICAL SKILL 1.1: A Brief History of C++

The history of C++ begins with C. The reason for this is easy to understand: C++ is built upon the

foundation of C. Thus, C++ is a superset of C. C++ expanded and enhanced the C language to support

object-oriented programming (which is described later in this module). C++ also added several other

improvements to the C language, including an extended set of library routines. However, much of the

spirit and flavor of C++ is directly inherited from C. Therefore, to fully understand and appreciate C++,

you need to understand the “how and why” behind C.

C: The Beginning of the Modern Age of Programming

The invention of C defines the beginning of the modern age of programming. Its impact should not be

underestimated because it fundamentally changed the way programming was approached and thought

about. Its design philosophy and syntax have influenced every major language since. C was one of the

major, revolutionary forces in computing.

C was invented and first implemented by Dennis Ritchie on a DEC PDP-11 using the UNIX operating

system. C is the result of a development process that started with an older language called BCPL. BCPL

was developed by Martin Richards. BCPL influenced a language called B, which was invented by Ken

Thompson and which led to the development of C in the 1970s.

Prior to the invention of C, computer languages were generally designed either as academic exercises or

by bureaucratic committees. C was different. It was designed, implemented, and developed by real,

working programmers, reflecting the way they approached the job of programming. Its features were

honed, tested, thought about, and rethought by the people who actually used the language. As a result,

C attracted many proponents and quickly became the language of choice of programmers around the

world.

C grew out of the structured programming revolution of the 1960s. Prior to structured programming,

large programs were difficult to write because the program logic tended to degenerate into what is

known as “spaghetti code,” a tangled mass of jumps, calls, and returns that is difficult to follow.

Structured languages addressed this problem by adding well-defined control statements, subroutines

C++ A Beginner’s Guide by Herbert Schildt

with local variables, and other improvements. Using structured languages, it became possible to write

moderately large programs.

Although there were other structured languages at the time, such as Pascal, C was the first to

successfully combine power, elegance, and expressiveness. Its terse, yet easy-to-use syntax coupled

with its philosophy that the programmer (not the language) was in charge quickly won many converts. It

can be a bit hard to understand from today’s perspective, but C was a breath of fresh air that

programmers had long awaited. As a result, C became the most widely used structured programming

language of the 1980s.

The Need for C++

Given the preceding discussion, you might be wondering why C++ was invented. Since C was a successful

computer programming language, why was there a need for something else? The answer is complexity.

Throughout the history of programming, the increasing complexity of programs has driven the need for

better ways to manage that complexity. C++ is a response to that need. To better understand the

correlation between increasing program complexity and computer language development, consider the

following.

Approaches to programming have changed dramatically since the invention of the computer. For

example, when computers were first invented, programming was done by using the computer’s front

panel to toggle in the binary machine instructions. As long as programs were just a few hundred

instructions long, this approach worked. As programs grew, assembly language was invented so that

programmers could deal with larger, increasingly complex programs by using symbolic representations

of the machine instructions. As programs continued to grow, high-level languages were developed to

give programmers more tools with which to handle the complexity.

The first widely used computer language was, of course, FORTRAN. While FORTRAN was a very

impressive first step, it is hardly a language that encourages clear, easy-to-understand programs. The

1960s gave birth to structured programming, which is the method of programming encouraged by

languages such as C. With structured languages it was, for the first time, possible to write moderately

complex programs fairly easily. However, even with structured programming methods, once a project

reaches a certain size, its complexity exceeds what a programmer can manage. By the late 1970s, many

projects were near or at this point.

In response to this problem, a new way to program began to emerge: object-oriented programming

(OOP). Using OOP, a programmer could handle larger, more complex programs. The trouble was that C

did not support object-oriented programming. The desire for an object-oriented version of C ultimately

led to the creation of C++.

In the final analysis, although C is one of the most liked and widely used professional programming

languages in the world, there comes a time when its ability to handle complexity is exceeded. Once a

program reaches a certain size, it becomes so complex that it is difficult to grasp as a totality. The

C++ A Beginner’s Guide by Herbert Schildt

purpose of C++ is to allow this barrier to be broken and to help the programmer comprehend and

manage larger, more complex programs.

C++ Is Born

C++ was invented by Bjarne Stroustrup in 1979, at Bell Laboratories in Murray Hill, New Jersey. He

initially called the new language “C with Classes.” However, in 1983 the name was changed to C++.

Stroustrup built C++ on the foundation of C, including all of C’s features, attributes, and benefits. He also

adhered to C’s underlying philosophy that the programmer, not the language, is in charge. At this point,

it is critical to understand that Stroustrup did not create an entirely new programming language.

Instead, he enhanced an already highly successful language.

Most of the features that Stroustrup added to C were designed to support object-oriented

programming. In essence, C++ is the object-oriented version of C. By building upon the foundation of C,

Stroustrup provided a smooth migration path to OOP. Instead of having to learn an entirely new

language, a C programmer needed to learn only a few new features before reaping the benefits of the

object-oriented methodology.

When creating C++, Stroustrup knew that it was important to maintain the original spirit of C, including

its efficiency, flexibility, and philosophy, while at the same time adding support for object-oriented

programming. Happily, his goal was accomplished. C++ still provides the programmer with the freedom

and control of C, coupled with the power of objects.

Although C++ was initially designed to aid in the management of very large programs, it is in no way

limited to this use. In fact, the object-oriented attributes of C++ can be effectively applied to virtually

any programming task. It is not uncommon to see C++ used for projects such as editors, databases,

personal file systems, networking utilities, and communication programs. Because C++ shares C’s

efficiency, much high-performance systems software is constructed using C++. Also, C++ is frequently

the language of choice for Windows programming.

The Evolution of C++

Since C++ was first invented, it has undergone three major revisions, with each revision adding to and

altering the language. The first revision was in 1985 and the second in 1990. The third occurred during

the C++ standardization process. Several years ago, work began on a standard for C++. Toward that end,

a joint ANSI (American National Standards Institute) and ISO (International Standards Organization)

standardization committee was formed. The first draft of the proposed standard was created on January

25, 1994. In that draft, the ANSI/ISO C++ committee (of which I was a member) kept the features first

defined by Stroustrup and added some new ones. But, in general, this initial draft reflected the state of

C++ at the time.

Soon after the completion of the first draft of the C++ standard, an event occurred that caused the

standard to be greatly expanded: the creation of the Standard Template Library (STL) by Alexander

Stepanov. The STL is a set of generic routines that you can use to manipulate data. It is both powerful

C++ A Beginner’s Guide by Herbert Schildt

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