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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.

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

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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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.

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

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!

close

Awesome!

Completion rate improved to 2.63

Swipe to show menu

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