货品的进出库模型

货品包括货号和重量属性，实现简单的入库出库统计功能，实例用于加深指针和链表的认识以及类的使用。

#include <iostream>
#include <string>
using namespace std;
class StockWeight
{
    public:
        StockWeight(int c,int w = 0):weight(w),code(c)
        {
            totalWeight += w;//入库总重量增加
            cout << c << "stock input! total " << totalWeight << endl;
        }
        ~StockWeight()
        {
            totalWeight -= weight;//出库析构总重量减少
            cout << code << "stock output! left " << totalWeight << endl;
        }
        int getCode()
        {
            return code;//返回货号
        }
        static int getTotalWeight()
        {
            return totalWeight;//返回总重量
        }
        StockWeight *next;
    private:
        int weight;//重量
        int code;//货号
        static int totalWeight;//静态成员 总共的重量
};
int StockWeight::totalWeight = 0;
void inputWeight(StockWeight *&head,int code,int w)
{
    StockWeight *g,*p = new StockWeight(code, w);//新对象结点
    p->next = NULL;
    if (head == NULL){head = p;return;}//链表没有内容
    //循环将新结点插入到最后
    g = head;
    while (g->next != NULL)
    {
        g = g->next;//指针挪动
    }
    g->next = p;
}
void outputWeight(StockWeight *&head, int code)
{
    StockWeight *g,*p;
    if (head == NULL){cout << " there is no goods!" << endl; return;}//链表没有内容
    g = head;//跟踪指针
    while (g->getCode() != code && g->next != NULL)//如果当前指针的code不等于特定的code 或者链表已经没有下一结点便停止循环
    {
        g = g->next;//指针挪动
    }
    if (g->getCode() != code) { cout << " there is no goods code " << code << endl; return; }//没找到货品code
    //找到了code
    //第一个结点特殊处理
    if (g == head){
        head = head->next;//头指针改变
        delete g;//出库析构
        return;
    }
    //遍历找出它的上结点
    p = head;
    while (p->next != g)
    {
        p = p->next;//指针挪动
        break;
    }
    p->next = g->next;//重指向
    delete g;//出库析构
}
void main()
{
    StockWeight *head = NULL;//链表头指针
    int leng,code,weight;//leng是指令。。code是货号。。weight是重量
    do
    {
        cin >> leng;//输入指令
        switch (leng)
        {
            case 1://入货
            {
                cout << "inputWeight:" << endl;//入库
                cout << "code:";
                cin >> code;//输入货号
                cout << "weight:";
                cin >> weight;//输入重量
                inputWeight(head, code, weight);//调用方法入库
                break;
            }
            case 2://出货
            {
                cout << "outputWeight:" << endl;//出库
                cout << "code:";
                cin >> code;//输入货号
                outputWeight(head, code);//调用方法出库
                break;
            }
            case 3://输出总重量
            {
                cout << "total Weight:" << StockWeight::getTotalWeight() << endl;
                break;
            }
            default:
                break;
        }
    } while (leng);//无限循环知道输入0
    getchar();
    getchar();
}