Statements in C, like statements in any other programming language,
consist almost entirely of expressions and special reserved words.
Declarations in C, unlike declarations in other languages, also contain
arbitrary expressions. Thus, studying the means by which C expressions
are constructed and evaluated is especially important-particularly since
the number of permissible C operators is so large. Since all of the
operands in a C expression (excluding constants) must be properly
declared before they are used, and since declarations themselves contain
expressions, the teaching of C involves the following chicken-and-egg
problem: Should one begin by considering only elementary declarations,
in which case the topic of expression construction and evaluation cannot
be fully treated in one place, because the operators that pertain to the
more complex objects-like pointers and structures (whose declarations
have not yet been introduced)--have not yet been covered, or should one
postpone entirely the issue of how decla- rations are written (merely
assuming that all of the objects under discussion have been properly
declared) in order to fully treat all types of operands and operators in
one comprehensive discussion? If the student is encouraged to begin
writing programs immediately, the former choice is mandatory, because
even the most elementary programs must vII Preface viii contain proper
declarations. Thus, most C textbooks postpone the discussion of objects
like arrays, structures, and pointers (and of the operators that pertain
to them) until the second half of the book is reached.
