Memory management cheatsheet for C/C++

Difference Between Heap and Stack Memory

Heap and stack memory are two areas of memory used for different purposes in programming:

Stack Memory

• Purpose: Used for storing temporary, local variables and function call information.
• Characteristics:
  • Automatically managed (allocated and deallocated when functions are called and return).
  • Follows a Last In, First Out (LIFO) structure.
  • Fast allocation and deallocation.
  • Size is usually limited and predefined.
• Example: Local variables declared in a function (int x = 10;).

Heap Memory

• Purpose: Used for dynamic memory allocation, where the lifetime of the memory can extend beyond the scope of the function.
• Characteristics:
  • Manually managed (you need to explicitly allocate and deallocate memory).
  • Larger in size compared to the stack.
  • Slower to allocate and deallocate because of the need for manual management.
  • Risk of memory leaks if not properly deallocated.
• Example: Allocating memory dynamically with malloc (C) or new (C++/Java).

Key Differences

Aspect	Stack	Heap
Management	Automatically managed	Manually managed
Speed	Faster	Slower
Lifetime	Tied to function scope	Can persist until explicitly freed
Size	Limited and small	Large and expandable
Errors	Stack overflow (exceeding limit)	Memory leaks or fragmentation