What is a pointer?

Learn that a pointer holds a memory address and is accessed with *.

What is a pointer?

A pointer is a variable that holds a memory address. It stores not an int itself, but its memory address. The syntax: int* p;. Here * says p is a pointer to int.

A pointer shows which variable it points to, so you can access that variable indirectly. Pointers are a powerful but delicate tool in C++; they let you manage memory directly, but mistakes cause undefined behavior. Unlike references, they can be null and can be re-bound.

Pointer versus reference

Pointers and references are similar but different. A reference is bound once and cannot be null; a pointer can be re-bound and can be nullptr. The syntax also differs: with a pointer you access the value via *p.

Pointers are used for dynamic memory, walking arrays, and expressing 'maybe empty' states. References are preferred when you need 'an alias for a variable that surely exists'. Both are useful in their own domain; which one to pick depends on the problem.

Exercise Access a value through a pointer

Declare int x = 42;. Bind p to x's address with int* p = &x;. Print the value p points to using *p with std::cout.

Show example solution

#include <iostream>

int main() {
    int x = 42;
    int* p = &x;
    std::cout << *p << "\n";
    return 0;
}

Test yourself

What is a pointer?
- A kind of array
- A variable that holds a memory address
- A memory block
- A kind of reference
Show answer

A variable that holds a memory address — A pointer is a variable that holds a memory address.

Pointer declaration

int x = 42;
int____ p = &x;

Show answer

int x = 42;
int* p = &x;

Match each expression to its meaning

int* p

Pointer declaration
&x

Take address
*p

Access value
42

Value

Next lesson: The & address operator

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