Difference between stack and pointer

 

Aspect	Stack	Pointer
Definition	A stack is a linear data structure that follows the LIFO (Last In, First Out) principle, where elements are added and removed from the same end (called the top).	A pointer is a variable that stores the memory address of another variable, allowing indirect access to that value.
Concept Type	Abstract data structure used for managing collections of elements.	Programming construct used to manage memory and reference variables indirectly.
Primary Use	Used for function call management, undo operations, expression evaluation, and recursive programming.	Used for dynamic memory allocation, data structures (like linked lists, trees), and passing arguments by reference.
Data Access	Access is restricted to the top of the stack only (no random access).	Provides direct access to memory locations; can point to any variable or structure in memory.
Memory Allocation	Usually uses the stack segment of memory (automatic storage).	Can point to memory in any segment, including heap, stack, or static memory.
Insertion/Removal	Only possible at one end (the top); uses push() and pop() operations.	No inherent insertion/removal; a pointer just holds or changes addresses.
Direction of Use	Grows vertically in memory (in downward or upward direction, depending on system architecture).	Moves horizontally through memory by arithmetic operations (pointer arithmetic).
Error Risk	May cause stack overflow if it exceeds its size limit (especially in recursive calls).	Improper use may lead to segmentation faults, memory leaks, or dangling pointers.
Access Method	Accessed through stack operations; does not allow direct memory addressing.	Accesses memory through dereferencing using * operator in languages like C/C++.
Language Implementation	Used internally by most languages to manage function calls and local variables.	Explicitly handled in languages like C, C++, and sometimes in low-level system code.
Example Use	Managing return addresses and local variables during recursive function calls.	Allocating memory dynamically using malloc() or new, and traversing data structures.
Analogy	Like a stack of plates—you can only take the top one off or add another on top.	Like a pointer or arrow—it tells you where something is located but not what it is.
Relation to Each Other	The call stack may store pointers as part of function frames (e.g., return address, base pointer).	A pointer can be used to implement stacks dynamically using arrays or linked lists.
Memory Management	Automatically managed by the system (stack frames created/destroyed).	Requires manual memory management, especially in C/C++.
Data Type	Abstract structure, not a specific type.	Data type that stores addresses, often typed (e.g., int *, char *).