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Oppiskele Pointer to Pointer Dynamic Allocation | Dynamic Memory Allocation
C++ Pointers and References
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C++ Pointers and References

C++ Pointers and References

1. Pointers Fundamentals
2. Pointer Arithmetic
3. References Fundamentals
4. Dynamic Memory Allocation

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

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#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)

Tehtävä

Swipe to start coding

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

Ratkaisu

cpp

solution

Switch to desktopVaihda työpöytään todellista harjoitusta vartenJatka siitä, missä olet käyttämällä jotakin alla olevista vaihtoehdoista
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Osio 4. Luku 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)

Tehtävä

Swipe to start coding

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

Ratkaisu

cpp

solution

Switch to desktopVaihda työpöytään todellista harjoitusta vartenJatka siitä, missä olet käyttämällä jotakin alla olevista vaihtoehdoista
Oliko kaikki selvää?

Miten voimme parantaa sitä?

Kiitos palautteestasi!

Osio 4. Luku 4
Switch to desktopVaihda työpöytään todellista harjoitusta vartenJatka siitä, missä olet käyttämällä jotakin alla olevista vaihtoehdoista
Pahoittelemme, että jotain meni pieleen. Mitä tapahtui?
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