C programming

• C


  • Easy to learn
  • Structured language
  • It produces efficient programs
  • It can handle low-level activities
  • It can be compiled on a variety of computers
• C Compilers


  Converts a program written in C language into a language understandable by a computer (machine language)
• Examples of C compilers

  • Turbo C
  • Borland C
• Parts of a C program

  • Preprocessor Commands
  • Functions
  • Variables
  • Statements & Expressions
  • Comments
• Preprocessor Commands


  Commands that tell the compiler to do preprocessing before doing actual compilation
• Functions


  Main building blocks of any C Program, including the mandatory main() function
• Variables

  Used to hold numbers, strings and complex data for manipulation
• Statements & Expressions


  Expressions combine variables and constants to create new values, Statements are expressions, assignments, function calls, or control flow statements which make up C programs
• Comments


  Used to give additional useful information inside a C Program
• C is a case sensitive programming language
• C has a free-form line structure, with the end of each statement marked by a semicolon
• Multiple statements can be on the same line in C
• White spaces (tab, space) are ignored in C
• Statements can continue over multiple lines in C
• Primary data types in C

  • Integer
  • Character
  • Floating Point
  • Double precision floating point
  • Void
• Integer Type


  Whole numbers with a machine dependent range of values, including short int, int, and long int with signed and unsigned forms
• Floating Point Types


  Represent real numbers, with float, double, and long double providing increasing precision
• Void Type


  Used to specify the type of a function that does not return a value
• Character Type


  Represents a single character, with signed and unsigned forms
• Size and range of data types on a 16-bit machine

  • Char/Signed Char
  • Unsigned Char
  • Int/Signed Int
  • Unsigned Int
  • Short Int/Signed Short Int
  • Unsigned Short Int
  • Long Int/Signed Long Int
  • Unsigned Long Int
  • Float
  • Double
  • Long Double
• Declaration of variables


  1. Tells the compiler the variable name

  2. Specifies the data type the variable will hold
• User-defined type declaration


  Allows defining an identifier that represents an existing data type, which can then be used to declare variables
• User-defined type declaration


  • typedef int salary;
  • typedef float average;
• Enumerated data type


  A user-defined data type where variables can only have one of the specified values
• Enumerated data type


  • enum day {Monday, Tuesday, ..., Sunday};
  • enum day week_st, week_end;
• C language instructions must strictly follow the predefined syntax rules
• Keywords


  Special words used exclusively by the C language, with their own meanings
• C language character set

  • Letters (uppercase A-Z, lowercase a-z)
  • Digits (0-9)
  • Special characters
  • Whitespace (blank, tab, newline, etc.)
• Identifiers


  Names of user-defined variables, arrays, and functions, which must follow specific rules
• Types of constants in C


  • Integer constants
  • Real constants
  • Single character constants
  • String constants
• Integer constants

  A sequence of digits
• Identifier

  The name of user-defined variables, array and functions
• Identifier

  • First character must be an alphabet (or underscore)
  • Identifier names must consists of only letters, digits and underscore
  • An identifier name should have less than 31 characters
  • Any standard C language keyword cannot be used as a variable name
  • An identifier should not contain a space
• Types of constants in C

  • Integer Constants
  • Real Constants
  • Single Character Constants
  • String Constants
• Integer Constants

  A sequence of digits, can be decimal, octal or hexadecimal
• Octal Integer Constants

  • O26
  • O
  • O347
  • O676
• Hexadecimal Integer Constants

  • OX2
  • OX8C
  • OXbcd
  • Ox
• Real Constants

  Numbers containing a fractional part, can also be represented in exponential notation
• Real Constants

  • 0.0026
  • -0.97
  • 435.29
  • +487.0
• Single Character Constants

  A single character enclosed in single quotes