C Programming Variables and Data Types

Variables

• In C, variables can be declared for different data types, such as int, char, float, and double.
• Example: double pi = 3.14159265359;

Derived Data Types

• C supports derived data types, including:
  • Arrays
  • Pointers
  • Structures
  • Unions
• These data types allow programmers to handle heterogeneous data, directly modify memory, and build complicated data structures.

Operators

• C language has a rich set of built-in operators, including:
  • Arithmetic Operators
  • Relational Operators
  • Logical Operators
  • Bitwise Operators
  • Assignment Operators
  • Misc Operators
• Each operator has a specific function, such as arithmetic, comparison, logical operations, etc.

Arithmetic Operators

• C supports the following arithmetic operators:
  • + (Addition)
  • - (Subtraction)
  • * (Multiplication)
  • / (Division)
  • % (Modulus Operator)
  • ++ (Increment)
  • -- (Decrement)

Relational Operators

• C supports the following relational operators:
  • == (Equality)
  • != (Inequality)
  • > (Greater Than)
  • < (Less Than)
  • >= (Greater Than or Equal To)
  • <= (Less Than or Equal To)

Constants

• In C, constants can be declared using:
  • const keyword
  • #define pre-processor
• Types of constants in C include:
  • Integer constants (e.g. 10, 11, 34)
  • Floating-point constants (e.g. 45.6, 67.8, 11.2)
  • Octal constants (e.g. 011, 088, 022)
  • Hexadecimal constants (e.g. 0x1a, 0x4b, 0x6b)
  • Character constants (e.g. 'a', 'b', 'c')
  • String constants (e.g. "java", "c++", ".net")

Special Characters in C

• Special characters in C have special meanings and cannot be used for other purposes:
  • Square brackets [] (used for subscripts)
  • Simple brackets () (used for function declaration and function calling)
  • Curly braces { } (used for opening and closing code blocks and loops)
  • Comma , (used for separating statements and function parameters)
  • Hash/pre-processor # (used for pre-processor directives)
  • Asterisk * (used for pointers and multiplication)
  • Tilde ~ (used as a destructor to free memory)
  • Period . (used to access members of a structure or union)