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C++ Pointers and References

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Pointer to Pointer Dynamic Allocation

A pointer to pointer, denoted as double pointer (**).

This is a pointer that holds the memory address of another pointer. In simple words, it is a variable whose value is the address of another pointer. This concept might sound complex at first, but it provides a powerful mechanism for dealing with advanced dynamic memory allocation.

Syntax

cpp

main

copy

              
12345678910111213

            
#include <iostream>

int main()
{
    int x = 10;
    int *ptr1 = &x;
    int **ptr2 = &ptr1;

    // Accessing values using double pointer
    std::cout << "Location of ptr2: " << ptr2 << std::endl;
    std::cout << "Location of ptr1: " << *ptr2 << std::endl;
    std::cout << "Value of x: " << **ptr2 << std::endl;
}

  • ptr1: is a pointer to an integer (int*);

  • ptr2: is a double pointer to an integer (int**).

Dynamic Allocation of a Two-Dimensional Array

If you want to create a two-dimensional array dynamically (at runtime) you have to use a pointer to a pointer for the rows.

And then initialize each row with dynamic array (like in previous chapter)

Uppgift

Swipe to start coding

  • Dynamically allocate a two dimensional array.
  • Dynamically allocate the arrays as elements.
  • Free all allocated memory.

Lösning

cpp

solution

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Avsnitt 4. Kapitel 4

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book
Pointer to Pointer Dynamic Allocation

A pointer to pointer, denoted as double pointer (**).

This is a pointer that holds the memory address of another pointer. In simple words, it is a variable whose value is the address of another pointer. This concept might sound complex at first, but it provides a powerful mechanism for dealing with advanced dynamic memory allocation.

Syntax

cpp

main

copy

              
12345678910111213

            
#include <iostream>

int main()
{
    int x = 10;
    int *ptr1 = &x;
    int **ptr2 = &ptr1;

    // Accessing values using double pointer
    std::cout << "Location of ptr2: " << ptr2 << std::endl;
    std::cout << "Location of ptr1: " << *ptr2 << std::endl;
    std::cout << "Value of x: " << **ptr2 << std::endl;
}

  • ptr1: is a pointer to an integer (int*);

  • ptr2: is a double pointer to an integer (int**).

Dynamic Allocation of a Two-Dimensional Array

If you want to create a two-dimensional array dynamically (at runtime) you have to use a pointer to a pointer for the rows.

And then initialize each row with dynamic array (like in previous chapter)

Uppgift

Swipe to start coding

  • Dynamically allocate a two dimensional array.
  • Dynamically allocate the arrays as elements.
  • Free all allocated memory.

Lösning

cpp

solution

Switch to desktopByt till skrivbordet för praktisk övningFortsätt där du är med ett av alternativen nedan
Var allt tydligt?

Hur kan vi förbättra det?

Tack för dina kommentarer!

Avsnitt 4. Kapitel 4
Switch to desktopByt till skrivbordet för praktisk övningFortsätt där du är med ett av alternativen nedan
Vi beklagar att något gick fel. Vad hände?
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