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cpp-pointers
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cpp-pointers
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.. _cpp-pointers-1:

cpp Pointers
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**if p is a pointer**

&p the memory address of p

\*p the content that p points to

p the content of p (or the address that p points to)

Dynamic memory allocation or alias
----------------------------------

**Useful but dangerous…**

.. code-block:: cpp

int *p,* q; // create two pointers, named p and q

p = new int; //

\*p = 100;

q = p;

\*q = 200;

q = new int;

*q =* p;

delete p; // give memory that p occupied back to operating system

p = NULL; // set p to memory address 0

delete q; // give memory that q occupied back to operating system

q = NULL; // set q to memory address 0

Dynamic Allocation for arrays
-----------------------------

.. code-block:: cpp

int size = 5; // create an integer int \*A; // create an array of
pointers

A = new int[ size ]; // Ask for a certain size for your array

A[0] = 10; // Give values to Array A[1] = 20; A[2] = 30; A[3] = 40; A[4]
= 50;

// 8 32 32 36 40 cout << &A << A << A + 0 << A + 1 << A + 2

// 10 28 30 cout << A[0] << A[1] << A[2]

// 10 10 28 30 cout << *A <<* A + 0 << A + 1 << \* A + 2

delete []A; A = NULL;