C Program Session 1

----------C Program---------------

Introduction
*C is a procedural programming language.
*Developed by Dennis Ritchie (1972).
*Mainly developed for an operating system.
*C++ is nearly a superset of C language
*There are few programs that may compile in C, but not in C++. Example : printf()

How do we compile and run a C program?
  Refer the below link for brief answer.
 https://www.geeksforgeeks.org/compiling-a-c-program-behind-the-scenes/

>>>>>>>>>>>>>>KEYWORDS<<<<<<<<<<<
Keywords are predefined, reserved words used in programming that have special meanings to the compiler. Keywords are part of the syntax and they cannot be used as an identifier.

Data Type --> int, char, float, double, unsigned, signed, long, short
Flow Control --> if , else, for, while, do, switch, case, break, default, goto, continue
Storage Classes --> Auto, Static, register, extern
Memory Related --> Const, volatile,sizeof
Userdifined Datatype -->  struct, union, typedef, enum
funtion Related --> void, return.

Reference Link
https://www.w3schools.in/c-tutorial/keywords/
https://youtu.be/v5QPk5GV4Qw

>>>>>>>>>>>IDENTIFIER<<<<<<<<<<<<<<<<
Identifier refers to name given to entities such as variables, functions, structures etc.

  RULES FOR IDENTIFIERS
>>An identifier can only have alphanumeric characters (a-z , A-Z , 0-9) (i.e. letters & digits) and underscore( _ ) symbol.
>>Identifier names must be unique cannot be repeated.
>>The first character must be an alphabet or underscore.
>>You cannot use a keyword as identifiers.You cannot use int as an identifier because int is a keyword
>>Only the first thirty-one (31) characters are significant.
>>It must not contain white spaces.
>>Identifiers are case-sensitive.

  Abc   Valid
  Abc1  Valid
  1Abc  Invalid
  1abc  Invalid
  @Ab    Invalid
  _abc    valid
  _      Valid
  #sd    invalid
  sd#    invalid
  $as    invalid
  as$     valid
  122    invalid


  Reference >>
  https://www.w3schools.in/c-tutorial/identifiers/
  https://youtu.be/3LY60I3TExE