Пример за работа с указатели в С++

#include <iostream>
#include <string>
using namespace std;

int main()
{

    // глава 9.1 - 9.6

    int i = 5;
    int* ip = &i;
    int arr[5] = { 1,2,3,4,5 };

    cout << "i = " << i << endl;

    cout << "&i = " << &i << endl;

    cout << "ip = " << ip << endl;

    cout << "&ip = " << &ip << endl;

    cout << "*ip = " << *ip << endl;

    cout << "&arr = " << &arr << endl;
    cout << "&arr[0] = " << &arr[0] << endl;
    cout << "&arr[1] = " << &arr[1] << endl;
    cout << "&arr[2] = " << &arr[2] << endl;
    cout << "&arr[3] = " << &arr[3] << endl;
    cout << "&arr[4] = " << &arr[4] << endl;

    cout << arr[0] << endl;
    ip = &arr[0];
    cout << *ip << endl;
    cout << "ip = " << ip << endl;
    ip = ip + 4;
    cout << "ip + 4 = " << ip << endl;
    cout << *ip << endl;
    cout << arr[4] << endl;

    // sizeof 9.2
    cout << "size of char:" << sizeof(char) << endl;
    cout << "size of int: " << sizeof(int) << endl;
    cout << "size of double: " << sizeof(double) << endl;
    cout << "size of 'A' :" << sizeof('A') << endl;
    cout << "size of (3+20): " << sizeof(3 + 20) << endl;
    cout << "size of (3*2.5): " << sizeof(3 * 2.5) << endl;
    int* sp;
    cout << "size of sp: " << sizeof sp << endl;
    cout << "size of int* :" << sizeof(int*) << endl;

    // 9.3. Адресна аритметика
    int mas[] = { 5,10,15,20,25,30,35,40,45,50 }; //3
    int *p1, *p2; //4
    p1 = &mas[3]; //5
    p2 = &mas[7];
    cout << "p1= " << p1 << '\t'; //7
    cout << "*p1= " << *p1 << endl; //8
    cout << "p2= " << p2 << '\t'; //9
    cout << "*p2= " << *p2 << endl; //10
    cout << "*(p1+1)= " << *(p1 + 1) << endl; //11
    cout << "*(p1-1)= " << *(p1 - 1) << endl; //12
    cout << "(p2-p1)= " << p2 - p1 << endl; //13
    p2++; //14
    cout << "*p2= " << *p2 << endl; //15
    p1 -= 2; //16
    cout << "*p1= " << *p1 << endl; //17


    // 9.4. Указатели към void
    { // правя фиктивен блок, за да мога да предефинирам
    int i = 25;
    double d = 2.5;
    void* p;
    p = &i; // p сочи данни от тип int
    // cout << *p; // грешно!
    cout << "p as int:" << *static_cast<int*>(p) << endl;
    p = &d; // p сочи данни от тип double
    cout << "p as double:" << *static_cast<double*>(p) << endl;
    }
    // динамична памет глава 9.7

    int* p = new int[10];
    *p = 11;
    cout << "p = " << p << endl;
    cout << "*p = " << *p << endl;
    cout << "p[0] = " << p[0] << endl;

    int n;
    cout << "n= "; cin >> n;
    double* dp = new double[n];
    cout << "dynamic array address after new " << dp << endl;
    for (int i = 0; i < n; i++)
        dp[i] = i;
    for (int i = 0; i < n; i++)
        cout << "dp[" << i << "] = " << dp[i] << endl;
    delete []dp;
    cout << "dynamic array address after delete " << dp << endl;

}