C Programming Basics

Header Files

• Header files contain pre-written code that provides access to functions and data structures.
• They allow programmers to reuse existing code, improving efficiency.
• Included using the #include directive.

Structure of a C Program

• Preprocessor directives are instructions processed before compilation.
  • #include directives include header files.
  • #define directives define constants or macros.
• main() Function is the entry point of execution for a C program.
• Body of main() { } contains the code that the program will execute.
• Global variables are declared outside of any function and are accessible from anywhere in the program.
• Local variables are declared inside functions and are only accessible within that function.

Comments

• Comments are annotations within the code, ignored by the compiler.
• Used to explain code logic, improve readability, and aid in maintenance.
• Can be single-line (using //) or multi-line (using /* ... */).

Constants and Variables

• Constants have fixed values throughout the program, cannot be modified.
• Variables can store data that can change during program execution.

Variable Naming Rules

• Variable names must start with a letter or underscore (_).
• They can contain letters, digits, and underscores.
• They are case-sensitive (e.g., age and Age are different).
• Avoid using keywords (e.g., int, float).

Data Types

Integer Data Type

• Stores whole numbers without decimal points.
• Examples: int, short, long.
• Size varies depending on the compiler and platform.

Floating-Point Data Type

• Stores numbers with decimal points.
• Examples: float, double, long double.
• Size varies depending on the compiler and platform.

Character Data Type

• Stores single characters.
• Uses single quotes (e.g., 'A', '!').
• Usually takes 1 byte of memory.

Declaring and Initializing Variables and Constants

• Declarations:
  • data_type variable_name; (without initialization)
  • data_type variable_name = value; (with initialization)
• Constant qualifiers:
  • const data_type variable_name = value;

Type Casting

• Implicit type casting is done automatically by the compiler when different data types are used in expressions.
• Explicit type casting is performed by the programmer using the (data_type) operator, forcefully converting one data type to another.

This quiz covers the fundamental concepts of C programming, including header files, program structure, and the types of variables. Participants will explore the preprocessor directives and the significance of comments in code. Test your knowledge of essential programming principles and improve your coding skills.