Lära Pointers | 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.

int* intPointer; // pointer to an int variable
double* doublePointer; // pointer to a double variable
char* charPointer; // pointer to a char variable

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

int x = 100; // variable
int* pX; // pointer to an int variable
pX = &x; // pX now points to x

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.

Main.c


              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

Main.c


              12345678910
            
#include <stdio.h>

int main()
{
    int* pX;

    printf("x = %p", pX);

    return 0;
}

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Determine the size of int and double pointers.

Lösning

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Avsnitt 6. Kapitel 3

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

int* intPointer; // pointer to an int variable
double* doublePointer; // pointer to a double variable
char* charPointer; // pointer to a char variable

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

int x = 100; // variable
int* pX; // pointer to an int variable
pX = &x; // pX now points to x

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.

Main.c


              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

Main.c


              12345678910
            
#include <stdio.h>

int main()
{
    int* pX;

    printf("x = %p", pX);

    return 0;
}

Uppgift

Swipe to start coding

Determine the size of int and double pointers.

Lösning

Byt till skrivbordet för praktisk övningFortsätt där du är med ett av alternativen nedan

Var allt tydligt?

Tack för dina kommentarer!

Avsnitt 6. Kapitel 3

single

Svep för att visa menyn

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

int* intPointer; // pointer to an int variable
double* doublePointer; // pointer to a double variable
char* charPointer; // pointer to a char variable

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

int x = 100; // variable
int* pX; // pointer to an int variable
pX = &x; // pX now points to x

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.

Main.c


              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

Main.c


              12345678910
            
#include <stdio.h>

int main()
{
    int* pX;

    printf("x = %p", pX);

    return 0;
}

Uppgift

Swipe to start coding

Determine the size of int and double pointers.

Lösning

Byt till skrivbordet för praktisk övningFortsätt där du är med ett av alternativen nedan

Var allt tydligt?

Tack för dina kommentarer!

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