Pointers

#include <iostream>
#include <stdlib.h>
#include <stdio.h>
#include <math.h>

using namespace std;

void Pointer()
{
    double **p = 0;
    try{
        p = new double *;
        *p = new double;
    } catch (const bad_alloc&) {
        cout << "out of memory!" << endl;
        delete p;
        return;
    }
    **p = 2;
    cout << " **p = " << **p << endl;
    delete *p;
    delete p;
}

void ArrayPointer()
{
    double **p = 0;
    int size;
    cout << "Input the size of array." << endl;
    cin >> size;
    try{
        p = new double *;
        *p = new double [size];
    } catch (const bad_alloc&) {
        cout << "out of memory!" << endl;
        delete p;
        return;
    }

    for (int i=0; i<size; i++)
        (*p)[i]=0;
    for (int i=0; i<size; i++)
        cout << (*p)[i] << " ";
    (*p)[0]=2.0;
    (*p)[size-1]=2.0;
    cout << endl;
    for (int i=0; i<size; i++)
        cout << (*p)[i] << " ";
    delete []*p;
    delete p;
}

void BigArrayPointer()
{

    double **p = 0;
    int size;
    cout << "Input the size of array." << endl;
    cin >> size;
    try{
        p = new double *[size];
    } catch (const bad_alloc&) {
        cout << "out of memory!" << endl;
        return;
    }
    for (int i=0; i<size; i++){
        try{
            p[i]=new double ;
        }    catch (const bad_alloc&) {
            cout << "out of memory!" << endl;

            for (int j=0; j<i; j++){
                delete p[j];
            }
            delete []p;
            return;
        }
    }

    for (int i=0; i<size; i++)
        *(p)[i]=0;

    for (int i=0; i<size; i++){
        cout << *(p[i]) << " ";
    }

    *(p[0])=2.0;
    *(p[size-1])=2.0;
    cout << endl;
    for (int i=0; i<size; i++)
        cout << *(p[i]) << " ";
    for (int i=0; i<size; i++)
        delete p[i];
    delete []p;
}

struct Sample
{
    char c;
    double x;
    int *p;
};

void SampleTask()
{

    Sample s;
    int n;
    double x;
    char c;
    cout << "Input the number of elements." << endl;
    cin >> n;
    s.p = new int [n];
    cout << "Input integer elements of array." << endl;
    for (int i=0; i<n ; i++)
        cin >> s.p[i];
    cout << "Input the number." << endl;
    cin >> s.x;
    cout << "Input the char." << endl;
    cin >> s.c;
    system("cls");
    for (int i=0; i<n ; i++)
        cout << s.p[i] << " ";
    cout << endl << "s.c = " << s.c << " s.x = " << s.x << endl;
    delete []s.p;
}

void DynamicSampleTask()
{
    Sample *a;
    int size, n;
    cout << "Input the number of elements in array of structures:" << endl;
    cin >> size;
    cout << "Input the number of elements in array:" << endl;
    cin >> n;
    try{
        a = new Sample [size];
    } catch (const bad_alloc&) {
        cout << "out of memory!" << endl;
        return;
    }

    for (int i = 0; i<size; i++) {
        try{
            a[i].p = new int [n]; // массив указателей на структуру,указывает на массив в структуре
        } catch (const bad_alloc&) {
            cout << "out of memory!" << endl;
            for (int j = 0; j<i; j++)
            {delete[] a[j].p;
            }
            delete []a;
            return;
        }
    }

    for (int i = 0; i<size; i++)
    {
        for (int j = 0; j<n; j++)
            a[i].p[j] = i;
    }

    for (int i = 0; i<size; i++)
    {
        for (int j = 0; j<n; j++)
            cout << a[i].p[j] << " ";
        cout << endl;
    }
    for (int i = 0; i<size; i++)
        delete []a[i].p;
    delete []a;
}

void DinamicPointer()
{
    Sample **a = 0;
    int size, n;
    cout << "Input the number of elements in array of structures." << endl;
    cin >> size;
    cout << "Input the number of elements in array." << endl;;
    cin >> n;
    try{
        a = new Sample *[size];
    } catch (const bad_alloc&) {
        cout << "out of memory!" << endl;
        return;
    }
    for (int i = 0; i<size; i++)
        try{
            a[i] = new Sample;
    } catch (const bad_alloc&) {

        cout << "out of memory!" << endl;
        for (int j = 0; j<i; j++)
        {
            delete a[j];
        }
        delete []a;
        return;
    }
    for (int i = 0; i<size; i++)
        try{
            a[i]->p = new int [n];
    } catch (const bad_alloc&) {
        cout << "out of memory!" << endl;
        for (int j = 0; j<i; j++)
            delete[] a[j]->p;



        for (int j = 0; j<size; j++)
            delete a[j];

        delete []a;
        return;
    }



    for (int i = 0; i<size; i++)
    {
        for (int j = 0; j<n; j++)
            (*(a[i])).p[j] = i;
    }
    for (int i = 0; i<size; i++)
    {
        for (int j = 0; j<n; j++)
            cout << (*(a[i])).p[j] << " ";
        cout << endl;
    }
    for (int i = 0; i<size; i++)
        delete [](*(a[i])).p;
    for (int i = 0; i<size; i++)
        delete a[i];
    delete []a;

}

int main()
{
    Pointer();
    //ArrayPointer();
    //BigArrayPointer();
    //SampleTask();
    //DynamicSampleTask();
    //DinamicPointer();
    system("pause");
}