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Learn Pointers | Pointers
C Basics

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Pointers

Using the reference operator & and the dereference operator *, we can create and work with pointers.

A pointer is a data type, just like int, char, or double. The pointer is designed to store an address, which you can obtain using the & operator. To declare a pointer, prepend it with the * character.

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In essence, a pointer is a variable that holds the address of another object.

python

Note

Typically, pointers are named by prefixing the letter p to the name of the object they're pointing to.

When you dereference a pointer, you access the value of the variable it points to.

c

Main

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#include <stdio.h> int main() { int x = 22543; // variable int* pX = &x; // `pX` is pointer to `x` printf("The value of `pX` is %p\n", pX); // value of pointer `pX` printf("The value of `x` by pointer `pX` is %d\n", *pX); // pointer dereference return 0; }

Note

*(&variable) == *pVariable

If you attempt to dereference a null pointer, the compiler will raise an error:

Example provided to showcase the mistake

c

Main

copy
12345678910
#include <stdio.h> int main() { int* pX; printf("x = %p", pX); return 0; }
Task

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Determine the size of int and double pointers.

Solution

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SectionΒ 6. ChapterΒ 3
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book
Pointers

Using the reference operator & and the dereference operator *, we can create and work with pointers.

A pointer is a data type, just like int, char, or double. The pointer is designed to store an address, which you can obtain using the & operator. To declare a pointer, prepend it with the * character.

python

In essence, a pointer is a variable that holds the address of another object.

python

Note

Typically, pointers are named by prefixing the letter p to the name of the object they're pointing to.

When you dereference a pointer, you access the value of the variable it points to.

c

Main

copy
1234567891011121314
#include <stdio.h> int main() { int x = 22543; // variable int* pX = &x; // `pX` is pointer to `x` printf("The value of `pX` is %p\n", pX); // value of pointer `pX` printf("The value of `x` by pointer `pX` is %d\n", *pX); // pointer dereference return 0; }

Note

*(&variable) == *pVariable

If you attempt to dereference a null pointer, the compiler will raise an error:

Example provided to showcase the mistake

c

Main

copy
12345678910
#include <stdio.h> int main() { int* pX; printf("x = %p", pX); return 0; }
Task

Swipe to start coding

Determine the size of int and double pointers.

Solution

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Everything was clear?

How can we improve it?

Thanks for your feedback!

SectionΒ 6. ChapterΒ 3
Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
We're sorry to hear that something went wrong. What happened?
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