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C Tutorials
➜ C Language
  - Features of C
  - First C Program
  - Compilation in C
  - C Character Set
  - Tokens
  - Keywords
  - Identifiers
  - Constants
  - Operators
  - Data Types
  - Variables
  - Type Casting
  - Comments
  - Input/Output
  - Escape Sequence
  - Programming Errors
➜ Control Statements
  - if Statement
  - if-else Statement
  - Nested if-else
  - else-if
  - switch Statement
  - Loop
  - while loop
  - do while loop
  - for loop
  - break
  - continue & goto
  - Nested Loop
  - Infinite Loop
➜ Functions
  - What is function
  - Call by Value & Reference
  - Recursive function
  - Storage Classes
➜ Array
  - 1-D Array
  - 2-D Array
  - Return an Array
  - Array to Function
➜ C Pointers
  - Pointers
  - Pointer to Pointer
  - Pointer Arithmetic
  - Dangling Pointers
  - sizeof() operator
  - const Pointer
  - void pointer
  - Dereference Pointer
  - Null Pointer
  - Function Pointer
  - Function pointer as argument
➜ Memory Management
  - Memory Layout of C
  - Dynamic memory
  - calloc()
  - malloc()
  - realloc()
  - free()
➜ Strings
  - gets() & puts()
  - String Functions
  - strlen()
  - strcpy()
  - strcat()
  - strcmp()
  - strrev()
  - strlwr()
  - strupr()
  - strstr()
➜ C Math
  - Math Functions
➜ Enum, Structure & Union
  - Enum
  - Structure
  - typedef
  - Array of Structures
  - Nested Structure
  - Structure Padding
  - Union
➜ File Handling
  - fprintf() fscanf()
  - fputc() fgetc()
  - fputs() fgets()
  - fseek()
  - EOF and feof()
  - fsetpos()
  - tmpfile()
  - rewind()
  - ftell()
  - lseek()
➜ Preprocessor
  - Preprocessor
  - Macros
  - #include
  - #define
  - #undef
  - #ifdef
  - #ifndef
  - #if
  - #else
  - #error
  - #pragma
➜ Command Line
  - Arguments

Identifiers in C Language

Each user-defined entities or elements in a C program are given a name to identify it uniquely during the program execution are called identifiers. In other words, an identifier can be defined as the user-defined name is given to identify variable, function, array, pointer, structure or a label. The name of identifier name should not be same as keywords or keywords are not used as identifiers.


The rules for naming an identifier

• First character should be an alphabet or underscore.
• Succeeding characters might be digits, letters or underscore.
• Punctuation and special characters aren't allowed except underscore.
• It must not contain white-space.
• It should be up to 31 characters long.
• Identifiers should not be keywords.


E.g. :
char ch='A';
Here ch is a name given to char type variable in above statement.




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