C and C++ are the world's most important programming language: Indeed, to be a professional programmer today implies proficiency in these two languages. They are the foundation upon which modern programming is built.
C was invented by Dennis Ritchie in the 1970s. C is a middle-level language. It combines the control structures of a high-level language with the ability to manipulate bits, bytes, and pointers (addresses). Thus, C gives the programmer nearly complete contra over the machine. C was first standardized late in 1989 when the American National Standards Institute (ANSI) standard for C was adopted. This version of C is commonly referred to as C89. This standard was also adopted by ISO (International Standards Organization). C89 was amended slightly in 1995.
C++ was created by Bjarne Stroustrup, beginning in 1979. The development and refinement of C++ was a major effort, spanning the 1980s and most of the 1990s. Finally, in 1998 an ANSI/ISO standard for C++ was adopted. In general terms, C++ is the object-oriented version of C. C++ is built upon the foundation of C89, including its 1995 amendments. In fact, the version of C defined by C89 is commonly referred to as the "C subset of C++," Although C++ began as a set of object-oriented extensions to C, it soon expanded into being a programming language in its own right. Today, C++ is nearly twice the size of the C language. Needless to say, C++ is one of the most powerful computer languages ever devised.
In 1999, a new ANSI/ISO standard for C was adopted. This version is called C99. It includes a number of refinements and several new features. Some of these "new" features were borrowed from C++, but some are entirely new innovations. Thus, several of the elements added by C99 are incompatible with C++. This means that with the advent of C99, Standard C is no longer a pure subset of C++, Fortunately, many of the incompatibilities relate to special-use features that are readily avoided. Thus, it is still easy to write code that is compatible with both C and C++. At the time of this writing, no major compiler currently accepts all of the C99 additions, but this is sure to change.
The following table synopsizes the relationships between C89, C99, and C++.
C89 The original ANSI/ISO standard for C. C89 is what most programmers today think of as C.
C++ The object-oriented version of C. The current ANSI/ISO standard for C++ is built upon C89. Thus, C89 forms a subset of C++.
C99 The latest standard for C. Includes all of C89, but adds several new features. Some of the new features are not supported by the current standard for C++.
The material in this book describes C89, C99, and C++, When a feature is unique to one of these, it will be so flagged. Otherwise, you can assume that the feature applies to all three.
As you are undoubtedly aware, C and C++ are large topics. It is, of course, not possible to cover every aspect of these important languages here. Instead, this quick reference distills their most salient features into a convenient and easy to use form.
