This chapter will introduce enough
C++ syntax and program construction concepts to allow you to write
and run some simple object-oriented
programs. In the subsequent chapter we will cover the basic syntax of C and C++
in detail.
By reading this chapter first,
you’ll get the basic flavor of what it is like to program with objects in
C++, and you’ll also discover some of the reasons for the enthusiasm
surrounding this language. This should be enough to carry you through Chapter 3,
which can be a bit exhausting since it contains most of the details of the C
language.
The user-defined data
type, or
class, is what distinguishes C++ from traditional
procedural languages. A class is a new data type that you or someone else
creates to solve a particular kind of problem. Once a class is created, anyone
can use it without knowing the specifics of how it works, or even how classes
are built. This chapter treats classes as if they are just another built-in data
type available for use in programs.
Classes that someone else has created are
typically packaged into a library. This chapter uses
several of the class libraries that come with all C++ implementations. An
especially important standard library is iostreams, which (among other things)
allow you to read from files and the keyboard, and to write to files and the
display. You’ll also see the very handy string class, and the
vector container from the Standard C++ Library. By the end of the
chapter, you’ll see how easy it is to use a pre-defined library of
classes.
In order to create your first program you
must understand the tools used to build
applications.
The process of language translation
All computer languages are translated
from something that tends to be easy for a human to understand (source
code) into something that is executed on a computer (machine
instructions). Traditionally, translators fall into
two classes: interpreters and
compilers.
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