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#include<iostream>

using namespace std;

int main()

{

    int a = 3;

    int b = 4;

    int c = 5;

    int d = 6;

    cout <<"a:"<< &a << endl;

    cout << "b:"<<&b << endl;

    cout << "c:"<<&c << endl;

    cout << "d:"<<&d << endl;

    return 0;

}

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#include<iostream>

using namespace std;

int main()

{

    int num = 10;

    while (num--)

    {

        int *p1 = (int*)malloc(sizeof(int));

        int *p2 = (int*)malloc(sizeof(int));

        cout <<"p1"<< p1 << endl;

        cout <<"p2"<<p2 << endl;

        cout << endl;

        free(p1);

    }

    return 0;

}

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//C++开辟动态内存的新玩法

//语法演示：

#include<iostream>

using namespace std;

int main()

{

    //申请一个int的动态空间

    int* p1 = (int*)malloc(sizeof(int));

    *p1 = 1;

    int* p2 = new int(2);//这里是初始化

    free(p1);

    delete p2;

    //申请一个10各int的动态数组

    int *p3 = (int*)malloc(sizeof(int)* 10);

    for (int i = 0; i < 10; i++)

    {

        p3[i] = i + 1;

    }

    int *p4 = new int[10]{1, 2, 3, 4, 5, 6, 7, 8, 9, 10};//初始化

    free(p3);

    delete[]p4;

    return 0;

}

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#include<iostream>

using namespace std;

struct ListNode

{

    int _val;

    ListNode* _next;

    ListNode* _prev;

    //构造函数

    ListNode(int val = 0)

    :_val(val)

    , _next(nullptr)

    , _prev(nullptr)

    {

        cout<<"ListNode(int val = 0)"<<endl;

    }

    ~ListNode()

    {

        cout << "ListNode()" << endl;

    }

};

int main()

{

    //申请一个结点的空间

    ListNode* pa = (ListNode*)malloc(sizeof(ListNode)*4);

    ListNode* pb = new ListNode(1);//不用去用sizeof去计算空间大小，很方便  

    free(pa);

    delete pb;

    //申请4个结点的空间--当然了一般不会这么玩儿，我们只是看看效果

    ListNode* pc = (ListNode*)malloc(sizeof(ListNode)* 4);

    ListNode* pd = new ListNode[4]{1, 2, 3, 4};

    free(pc);

    delete[]pd;

    return 0;

}