C h a p t e r 1 : A n O v e r v i e w o f C
5 that most programmers think of as “C” and that all mainstream compilers recognize.
Furthermore, it is C89 that forms the C subset of C++. Although several of the new features added by C99 will eventually find their way into the next standard for C++, currently these new features are incompatible with C++.
Because C89 is the standard that forms the C subset of C++, and because it is the version of C that the vast majority of C programmers currently know, it is the version of C discussed in Part I. Thus, when the term C is used, take it to mean the C defined by C89. However, important differences between C89 and C99 that relate specifically to
C++ are noted, such as when C99 adds a feature that improves compatibility with C++.
C Is a Middle-Level Language
C is often called a middle-level computer language. This does not mean that C is less powerful, harder to use, or less developed than a high-level language such as BASIC or
Pascal; nor does it imply that C has the cumbersome nature of assembly language (and its associated troubles). Rather, C is thought of as a middle-level language because it combines the best elements of high-level languages with the control and flexibility of assembly language. Table 1-1 shows how C fits into the spectrum of computer languages.
As a middle-level language, C allows the manipulation of bits, bytes, and addresses— the basic elements with which the computer functions. Despite this fact, C code is also
Highest level
Middle level
Ada
Modula-2
Pascal
COBOL
FORTRAN
BASIC
Java
C#
C++
C
Forth
Lowest level
Macro-assembler
Assembler
Table 1-1.
C’s Place in the World of Languages
