Pointer vs. Reference — What's the Difference?
By Maham Liaqat & Urooj Arif — Updated on May 19, 2024
A pointer stores the memory address of a variable, whereas a reference is an alias for an existing variable.
Difference Between Pointer and Reference
Table of Contents
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Key Differences
A pointer is a variable that holds the memory address of another variable. It allows direct manipulation of memory and is commonly used in languages like C and C++ for dynamic memory allocation and array handling. A reference, on the other hand, is an alias for another variable. Introduced in C++, a reference provides a way to access a variable using a different name. Unlike pointers, references cannot be null and must be initialized when declared.
Pointers provide flexibility and control over memory, which can be both powerful and dangerous if not managed correctly. References offer simplicity and safety by ensuring that they always refer to valid objects, eliminating many of the risks associated with pointers. In summary, pointers are versatile tools for low-level memory management, while references offer a higher level of abstraction and security.
Comparison Chart
Definition
Variable holding the address of another variable
Alias for another variable
Syntax
Int* ptr = &var;
Int& ref = var;
Nullability
Can be null
Cannot be null
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Reassignment
Can be reassigned to point to different variables
Cannot be reassigned
Initialization
Can be declared without initialization
Must be initialized at declaration
Dereferencing
Requires explicit dereferencing (*ptr)
Implicit dereferencing
Compare with Definitions
Pointer
Array manipulation: Allows traversal and manipulation of arrays.
Int* p = arr; p[2] = 5;
Reference
Function parameters: Passed to functions to avoid copying.
Void func(int& r) { r = 10; }
Pointer
Dynamic memory: Used to allocate and manage memory dynamically.
Int* arr = new int[10];
Reference
Const reference: Can refer to a constant variable.
Const int& cr = x;
Pointer
Memory address holder: A variable that stores the address of another variable.
Int* p = &x;
Reference
Cannot be null: Always refers to a valid object.
Int& r = x; (must initialize)
Pointer
Function parameters: Passed to functions to modify arguments.
Void func(int* p) { *p = 10; }
Reference
Reference is a relationship between objects in which one object designates, or acts as a means by which to connect to or link to, another object. The first object in this relation is said to refer to the second object.
Pointer
Null pointer: Can be set to null to indicate it points to nothing.
Int* p = nullptr;
Reference
The act of referring to something
Filed away the article for future reference.
Pointer
A long tapered stick or a laser beacon used to call attention to objects, as on a chart or blackboard.
Reference
Significance for a specified matter; relation or relationship
Her speeches have special reference to environmental policy.
Pointer
A scale indicator on a watch, balance, or other measuring instrument.
Reference
Meaning or denotation
The reference of the word “lion” is to a kind of wild cat.
Pointer
A dog of a breed developed in Europe to point game, having a smooth, short-haired coat that is often white with black or brownish markings.
Reference
A mention of an occurrence or situation
Made frequent references to her promotion.
Pointer
A dog of any of various similar breeds.
Reference
A note in a publication referring the reader to another passage or source.
Pointer
A piece of advice; a suggestion
Let me give you a few pointers on your golf swing.
Reference
The passage or source so referred to.
Pointer
A piece of indicative information
Interest rates and other pointers in the economic forecast.
Reference
A work frequently used as a source.
Pointer
(Computers) A variable that holds the address of a core storage location.
Reference
A mark or footnote used to direct a reader elsewhere for additional information.
Pointer
(Computers) A symbol appearing on a display screen in a GUI that lets the user select a command by clicking with a pointing device or pressing the enter key when the pointer symbol is positioned on the appropriate button or icon.
Reference
Submission of a case to a referee.
Pointer
Either of the two stars in the Big Dipper, Dubhe and Merak, that are aligned so that a line drawn between them extends north to Polaris, the north star.
Reference
Legal proceedings conducted before or by a referee.
Pointer
Anything that points or is used for pointing.
Reference
A person who recommends another or who can vouch for another's fitness or qualifications, as for a job.
Pointer
A teacher's pointer, pointing stick, a rod with an arrow.
Reference
A statement about a person's qualifications, character, and dependability.
Pointer
A needle-like component of a timepiece or measuring device that indicates the time or the current reading of the device.
Reference
To supply (a text) with references
The author hadn't adequately referenced the third chapter, so the copyeditor suggested adding more citations. This article is thoroughly referenced with up-to-date sources.
Pointer
(hunting) A breed of hunting dog, trained to point out game.
Reference
To cite as a reference
The monograph doesn't reference any peer-reviewed articles.
Pointer
(programming) A variable that holds the address of a memory location where a value can be stored.
Reference
Usage Problem To mention or allude to
The comedian's monologue referenced many Hollywood stars.
Pointer
(graphical user interface) An icon that indicates the position of the pointing device, such as a mouse.
Reference
A relationship or relation (to something).
Pointer
A tip, a bit of advice.
The instructor gave me some pointers on writing a good paper.
Reference
A measurement one can compare (some other measurement) to.
Pointer
Something that gives a point sharp end to something.
Pencil pointer
Reference
Information about a person, provided by someone (a referee) with whom they are well acquainted.
Pointer
(in combinations) Something worth a given number of points.
A ten-pointer
Reference
A person who provides this information; onlyn in UK English: a referee.
Pointer
One who, or that which, points.
Reference
A reference work.
Pointer
A mark to indicate a direction or relation
Reference
(attributive) That which serves as a reference work.
Reference Dictionary of Linguistics
Pointer
An indicator as on a dial
Reference
The act of referring: a submitting for information or decision.
Pointer
(computer science) indicator consisting of a movable spot of light (an icon) on a visual display; moving the cursor allows the user to point to commands or screen positions
Reference
(semantics) A relation between objects in which one object designates, or acts as a means by which to connect to or link to, another object.
Pointer
A strong slender smooth-haired dog of Spanish origin having a white coat with brown or black patches; scents out and points game
Reference
(academic writing) A short written identification of a previously published work which is used as a source for a text.
Reference
(academic writing) A previously published written work thus indicated; a source.
Reference
(computing) An object containing information which refers to data stored elsewhere, as opposed to containing the data itself.
Reference
A special sequence used to represent complex characters in markup languages, such as
™ for the ™ symbol.Reference
(obsolete) Appeal.
Reference
To provide a list of references for (a text).
You must thoroughly reference your paper before submitting it.
Reference
To refer to, to use as a reference.
Reference the dictionary for word meanings.
Reference
To mention, to cite.
In his speech, the candidate obliquely referenced the past failures of his opponent.
Reference
(programming) To contain the value that is a memory address of some value stored in memory.
The given pointer will reference the actual generated data.
Reference
The act of referring, or the state of being referred; as, reference to a chart for guidance.
Reference
That which refers to something; a specific direction of the attention; as, a reference in a text-book.
Reference
Relation; regard; respect.
Something that hath a reference to my state.
Reference
One who, or that which, is referred to.
Reference
The act of submitting a matter in dispute to the judgment of one or more persons for decision.
Reference
Appeal.
Reference
A remark that calls attention to something or someone;
She made frequent mention of her promotion
There was no mention of it
The speaker made several references to his wife
Reference
A short note recognizing a source of information or of a quoted passage;
The student's essay failed to list several important citations
The acknowledgments are usually printed at the front of a book
The article includes mention of similar clinical cases
Reference
An indicator that orients you generally;
It is used as a reference for comparing the heating and the electrical energy involved
Reference
A book to which you can refer for authoritative facts;
He contributed articles to the basic reference work on that topic
Reference
A formal recommendation by a former employer to a potential future employer describing the person's qualifications and dependability;
Requests for character references are all to often answered evasively
Reference
The most direct or specific meaning of a word or expression; the class of objects that an expression refers to;
The extension of `satellite of Mars' is the set containing only Demos and Phobos
Reference
The act of referring or consulting;
Reference to an encyclopedia produced the answer
Reference
A publication (or a passage from a publication) that is referred to;
He carried an armful of references back to his desk
He spent hours looking for the source of that quotation
Reference
The relation between a word or phrase and the object or idea it refers to;
He argued that reference is a consequence of conditioned reflexes
Reference
Refer to;
He referenced his colleagues' work
Reference
Alias for variable: A reference to another variable.
Int& r = x;
Reference
Simpler syntax: No need for dereferencing syntax.
R = 20; (direct assignment)
Common Curiosities
Can pointers be null?
Yes, pointers can be null, indicating they point to no valid memory location.
How do you declare a pointer?
A pointer is declared with an asterisk, e.g., int* ptr;
What is a reference?
A reference is an alias for another variable, allowing direct access to that variable.
Do references require dereferencing?
No, references automatically dereference, making their use simpler.
What is a pointer?
A pointer is a variable that stores the memory address of another variable.
Can you reassign a reference?
No, once a reference is initialized to a variable, it cannot be changed to refer to another variable.
How do you declare a reference?
A reference is declared with an ampersand, e.g., int& ref = var;
Can you reassign a pointer?
Yes, pointers can be reassigned to point to different variables or addresses.
Can references be null?
No, references must always refer to a valid object.
What is dereferencing?
Dereferencing is accessing the value stored at the address a pointer holds, using the asterisk (*) operator.
Are pointers or references safer?
References are generally safer because they cannot be null and must always refer to valid objects.
What happens if you dereference a null pointer?
Dereferencing a null pointer leads to undefined behavior and typically causes a program crash.
In what scenarios are references preferred?
References are preferred in function parameters and return types for simplicity, safety, and avoiding the overhead of copying objects.
In what scenarios are pointers preferred?
Pointers are preferred for dynamic memory allocation, complex data structures like linked lists, and situations requiring direct memory manipulation.
Can a reference be uninitialized?
No, a reference must be initialized when it is declared.
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Written by
Maham Liaqat
Co-written by
Urooj ArifUrooj is a skilled content writer at Ask Difference, known for her exceptional ability to simplify complex topics into engaging and informative content. With a passion for research and a flair for clear, concise writing, she consistently delivers articles that resonate with our diverse audience.
