/*

某商店经销一种货物，货物的购进和卖出以箱为单位，各箱的重量不一样，

因此商店需要目前库存的总重量。

现在用c++模拟商店货物购进和卖出的情况

*/

#include<iostream>

using namespace std;

//货物类

class Goods{

public:

    Goods(int w=){

        this->weight = w;

    }

    int GetW(){

        return weight;

    }

    Goods *next;

private:

    //重量

    int weight;

};

//商店类

class Shop{

public:

    Shop(int s=){

        this->weights = s;

        pHead = NULL;

    }

    ~Shop(){

        if (pHead!=NULL)

        {

            Goods *pCurrent = pHead;

            Goods *pNext = NULL;

            while (pCurrent){

                pNext = pCurrent->next;

                delete pCurrent;

                pCurrent = NULL;

                pCurrent = pNext;

            }

        }

        weights = ;

    }

    //卖出

    void SellOut(){

        if (pHead==NULL)

        {

            cout << "商店里已经没有货物了！" << endl;

        }

        else{

            //队列  先进先出

            Goods *pCurrent = pHead;

            pHead = pHead->next;

            delete pCurrent;

        }

    }

    //购进

    void Purchase(Goods *&pin){

        if (pHead==NULL)

        {

            //插入第一箱货物

            pHead = pin;

            weights += pin->GetW();

        }

        else{

            Goods *pCurrent = pHead;

            while (pCurrent->next){

                pCurrent = pCurrent->next;

            }

            pCurrent->next = pin;

            weights += pin->GetW();

        }

    }

    //查询货物重量

    int GetWeight(){

        return weights;

    }

private:

    int weights;

    Goods *pHead;

};

void protectA(){

    Shop *sp = new Shop();

    int indexover = ;

    while (indexover){

        int num = ;

        int w = ;

        cout << "请输入操作：" << endl;

        cout << "1购进货物" << endl;

        cout << "2卖出货物" << endl;

        cout << "3查看现有货物重量" << endl;

        cout << "按任意键退出" << endl;

        cin >> num;

        switch (num)

        {

        case :

            cout << "请输入货物的重量" << endl;

            //备注：在c++中不可以在case语句里定义任意变量,如果非要定义，请外面套上大括号{}

            //int ss = 0;

            //报错 ： error C2360: “ss”的初始化操作由“case”标签跳过

            {

                cin >> w;

                Goods * g1 = new Goods(w);

                sp->Purchase(g1);

            }

            break;

        case :

            {

                sp->SellOut();

            }

            break;

        case :

            cout << "现有货物的重量是" << sp->GetWeight() << endl;

            break;

        default:

            indexover = ;

            break;

        }

    }

    if (sp!=NULL)

    {

        delete sp;

    }

}

void main(){

    protectA();

    system("pause");

}