C Functions and Preprocessor Directives

C Functions

• Declaration: A function declaration tells the compiler about the function's name, return type, and parameters.
• Definition: A function definition provides the actual code that the function will execute.
• Scope: The scope of a function defines the region of the program where the function can be accessed.
• Recursion: Functions can call themselves, enabling recursive solutions for problems.
• Call by Value: Arguments are copied into the function, changes to the function arguments do not affect the original variables.
• Call by Reference: Arguments are passed as pointers, allowing the function to directly modify the original variables.

Preprocessor Directives

• #define: A preprocessor directive used to define constants or macros.
• Macros with Arguments: Macros can take parameters, allowing for flexible code substitution.
• Nested Macros: One macro can call another, enabling complex preprocessor operations.
• # Operator: Concatenates two tokens together during preprocessing.
• ## Operator: Concatenates two tokens together into a single token during preprocessing.

Storage Classes

• Automatic: Variables declared within a function, they are created when the function is called, and destroyed when the function ends.
• External (Global): Variables declared outside of any function, they are accessible from all parts of the program.
• Static: Variables declared with the static keyword retain their value throughout the program's execution, even after the function they're in has ended.
• Register: Variables declared with the register keyword are stored in the CPU's registers for faster access.

Arrays

• One-dimensional Arrays (1D): A contiguous block of memory storing elements of the same data type.
• Two-dimensional Arrays (2D): Represent matrices or tables, with rows and columns.
• Strings: A special type of array used to store characters, often terminated by a null character (\0).

Pointers

• Pointer Basics: A pointer variable stores the memory address of another variable.
• Pointer Arithmetic: Mathematical operations on pointers to navigate through memory.
• Pointer to Pointer: A pointer that stores the address of another pointer.
• Array & Pointer Relationship: An array name can be treated as a pointer to its first element.
• Array of Pointers: An array where each element is a pointer to a data type.
• Pointers to Functions: A pointer that points to a function, enabling function calls through pointers.
• Returning Pointers: Functions can return pointers to various data types for efficient data manipulation.

Dynamic Memory Allocation

• Dynamic Memory Allocation: Allocating memory at runtime, enabling programs to adjust their memory usage based on needs.
• Functions like malloc(), calloc(), realloc(), and free() are used for dynamic memory allocation and deallocation.

This quiz covers essential concepts of C programming, focusing on function declarations, definitions, scope, recursion, and the differences between call by value and call by reference. Additionally, it explores preprocessor directives like #define and macros, enhancing your understanding of code substitution and manipulation in C. Test your knowledge with this comprehensive quiz!