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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.

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

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Thanks for your feedback!

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
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