Introduction

Writer prefer 1983 ANSI C (K&R 2nd).

  • C was born for UNIX

    • C is machine independent
    • C is simple and concise (even though program with it is complicated)

  • Creator’s words

    • C is a general-purpose programming language which features economy of expression, modern control flow and data structures, and a rich set of operators.

    • C wears well as one’s experience with it grows.

    • C is a relatively “low level” language.

  • standard library

    • input output
    • memory management
    • string manipulation
    • etc

  • What C provides

    • data types
      • characters
      • integers
      • floating point numbers
      • and hierarchy of derived data types created with pointers, arrays, structures, and unions
    • expressions are formed from operators and operands
      • any expression, including an assignment or a function call, cam be statement
    • pointers provide for machine-independent address arithmetic
    • control-flow
      • statement grouping
      • decision making (if-else)
      • selecting one of a set of possible cases (switch)
      • looping
        • with the termination test at the top (while, for)
        • with the termination test at the bottom (do)
        • early loop exit (break)
        • early loop skip (continue)
    • Function
      • returns data type
      • may be called recursively
      • may exist in separated source files that are compiled separately
    • Variables
      • declared autoatically
      • may be declared in block-structure
      • may be internal to function, external but known only within source files, and conditional compilation
    • C is a relatively “low level” language
      • deals with characters, numbers, and addresses
      • there are no operations that manipulate an entire array or string
        • although structures may be copied as a unit
      • stirage allocation facility
        • static definition
        • stack discipline provided by the local variables of functions
        • there is no heap or garbage collection (?)
    • Input / Output
      • C itself provides no input/output facilities
        • no READ, WRITE statement
        • no built-in file access methods
      • input/output provided by explicitly-called functions
    • C supports only single-thread control flow (?)
      • tests, loops, grouping, subprograms
      • no multiprogramming