#include "pch.h"

#include <iostream>

using namespace std;

class goods {

public:

    goods(int w) {

        weight = w;

        total_weight += w;

    }

    ~goods() {

        total_weight -= weight;

    }

    static int total_weight_fun() {//类的函数，不能访问普通成员变量和普通函数

        return total_weight;

    }

    goods *next;

private:

    int weight;

    static int total_weight;//类的成员

};

int goods::total_weight = ;//声明与定义静态数据成员

void purchase(goods *&front, goods *&rear, int w) {

    goods *p = new goods(w);

    p->next = NULL;

    if (front == NULL) {

        front = rear = p;

    }

    else {

        rear->next = p;

        rear = rear->next;

    }

}

void sale(goods *&front, goods *&rear) {

    if (front == NULL) {

        cout << "no any goods" << endl;

        return;

    }

    goods *q = front;

    front = front->next;

    delete q;

    cout << "sale front goods" << endl;

}

int main()

{

    goods *front = NULL, *rear = NULL;

    int choice;

    int weight;

    do {

        cout << "Key in 1 is purchase,\nKey in 2 is sale,\nKey in 0 is over.\n";

        cin >> choice;

        switch(choice) {

            case :

            {

                cout << "input weiht:";

                cin >> weight;

                purchase(front, rear, weight);

                break;

            }

            case :

            {

                sale(front, rear);

                break;

            }

            case :

                break;

        }

        cout << "now total weight is: "<< goods::total_weight_fun()<<endl;

    } while (choice);

    cout << "exit!\n";

}