C Language Memory Management

C Language Study Notes

Memory Management

• Static Memory Allocation

  • Fixed size at compile time.
  • Variables declared outside functions or with the static keyword.

• Dynamic Memory Allocation

  • Managed at runtime using malloc(), calloc(), realloc(), and free().
  • Allows for flexible memory use, but requires manual management to avoid memory leaks.

• Stack vs Heap

  • Stack: Memory allocated for function calls; automatic deallocation.
  • Heap: Memory allocated dynamically; manual deallocation.

Syntax and Semantics

• Syntax

  • C is case-sensitive.
  • Statements end with a semicolon (;).
  • Curly braces {} are used to define blocks of code.

• Semantics

  • Refers to the meaning of syntactically valid statements.
  • Important to understand how code executes and the behavior of operations.

Data Types and Variables

• Basic Data Types

  • int: Integer type.
  • float: Single precision floating point.
  • double: Double precision floating point.
  • char: Single character.

• Derived Data Types

  • Arrays: Collection of elements of the same type.
  • Structures: Group of different types under one name.
  • Unions: Similar to structures but share the same memory location.

• Variable Declaration

  • Must be declared before use.
  • Syntax: <data_type> <variable_name>;

Control Structures

• Conditional Statements

  • if, else if, else: Execute blocks based on conditions.
  • switch: Selects one of many blocks based on variable values.

• Looping Constructs

  • for: Use when the number of iterations is known.
  • while: Use when the number of iterations is unknown; based on a condition.
  • do while: Executes at least once before checking the condition.

Functions and Pointers

• Functions

  • Defined using the syntax: <return_type> <function_name>(<parameters>).
  • Can return values and accept parameters.
  • Support recursion (functions calling themselves).

• Pointers

  • Variables that store memory addresses.
  • Syntax: <data_type> *<pointer_name>;
  • Used for dynamic memory allocation, array manipulation, and function arguments.

• Pointer Arithmetic

  • Can increment/decrement pointers to traverse arrays.
  • Care must be taken to stay within allocated memory bounds.

Memory Management

• Static Memory Allocation
  • Allocates fixed sizes for variables determined at compile time.
  • Static variables are declared outside of functions or with the static keyword.
• Dynamic Memory Allocation
  • Utilizes functions such as malloc(), calloc(), realloc(), and free() for memory management at runtime.
  • Provides flexibility in memory usage, requiring careful management to prevent memory leaks.
• Stack vs Heap
  • Stack memory is allocated for function calls and automatically deallocated.
  • Heap memory is allocated dynamically and requires manual deallocation efforts by the programmer.

Syntax and Semantics

• Syntax
  • C is a case-sensitive programming language.
  • Every statement must be terminated with a semicolon (;).
  • Curly braces {} are utilized to denote code blocks.
• Semantics
  • Refers to the interpretation and behavior associated with syntactically valid statements, which is crucial for understanding code execution.

Data Types and Variables

• Basic Data Types
  • int: Represents integer values.
  • float: Represents single-precision floating-point numbers.
  • double: Represents double-precision floating-point numbers.
  • char: Represents a single character.
• Derived Data Types
  • Arrays provide collections of elements of the same type.
  • Structures allow grouping of different types under a single name.
  • Unions enable storing different data types in the same memory location.
• Variable Declaration
  • All variables must be declared prior to their usage.
  • Syntax for declaration follows the pattern data_type variable_name;.

Control Structures

• Conditional Statements
  • if, else if, and else execute different code blocks based on specified conditions.
  • switch statement allows selection among multiple blocks based on variable values.
• Looping Constructs
  • for loops are suitable for a known number of iterations.
  • while loops operate when the number of iterations is uncertain and are based on conditions.
  • do while loops ensure the code block executes at least once before the condition is evaluated.

Functions and Pointers

• Functions
  • Function definitions follow the syntax: return_type function_name(parameters).
  • Functions can return values and accept parameters, facilitating modular programming.
  • Recursion is supported where functions can invoke themselves.
• Pointers
  • Pointers are variables that hold the memory address of another variable.
  • Pointer syntax is denoted by *, indicating a pointer type.
  • Pointers are essential for dynamic memory allocation, array manipulation, and passing arguments to functions.
• Pointer Arithmetic
  • Pointers can be incremented or decremented to traverse through arrays effectively.
  • It's important to stay within the boundaries of allocated memory to avoid undefined behavior.

Test your knowledge of memory management in C language, covering topics such as static and dynamic memory allocation, the stack vs heap distinction, and syntax and semantics of C. Understand the importance of memory management for efficient coding practices.