main.cpp

小型超市的库存管理系统

#include <iostream>
#include <cstring>
using namespace std;

struct inv
{
    char item[40];
    double cost;
    double retail;
    int on_hand;
    int lead_time;
    inv *next;
};

//建立商品信息库
inv *creat()
{
    inv *head, *tail, *pro;
    head = tail = NULL;
    cout << "Please initialize first:" << endl;
    while (1)
    {
        pro = new inv;
        pro -> next = NULL;
        cout << "Item: ";
        cin >> pro -> item;

        //如果输入商品名字为0，结束
        if (pro -> item[0] == '0')
        {
            delete pro;
            break;
        }

        cout << "Cost: ";
        cin >> pro -> cost;
        cout << "Retail: ";
        cin >> pro -> retail;
        cout << "on_hand: ";
        cin >> pro -> on_hand;
        cout << "Lead_time: ";
        cin >> pro -> lead_time;

        //如果链表为空，加入第一个结点
        if (tail == NULL)
            head = tail = pro;
        else
        {
            //如果链表中已经有其他点，将新结点加入链表结尾
            tail -> next = pro;
            tail = pro;
        }
    }
    cout << endl;
    return head;
}

//选择菜单
char manu()
{
    char str;
    do
    {
        cout << "e: enter new information" << endl;
        cout << "d: display all of them" << endl;
        cout << "r: delete one of them" << endl;
        cout << "u: update one of them" << endl;
        cout << "v: view one of them" << endl;
        cout << "q: quit" << endl << endl;
        cout << "choose one: ";
        cin >> str;
    }
    while (!strchr("edruvq", tolower(str)));
    return str;
}

//输出所有库存信息
void display(inv *pro)
{
    //如果链表为空，输出提示语句
    if (pro == NULL)
    {
        cout << "Link is NULL!" << endl << endl;
        return;
    }

    inv *p;
    p = pro;

    //如果链表不为空，输出库存信息
    while (p != NULL)
    {
        cout << "Items: " << p -> item << endl;
        cout << "Cost: " << p -> cost << endl;
        cout << "Retail price: " << p -> retail << endl;
        cout << "On hand: " << p -> on_hand << endl;
        cout << "Lead time to resupply: " << p -> lead_time << endl;
        cout << endl;
        p = p -> next;
    }
}

//输入新产品信息
inv *enter(inv *pro)
{
    inv *tail, *p;
    tail = pro;

    //如果链表不为空，找到链表结尾
    if (tail != NULL)    //*********必须加这一步判断，否则链表为空时，输入产品信息会出错
    {
        while (tail -> next != NULL)
            tail = tail -> next;
    }
    //申请结点，存入新产品信息
    p = new inv;
    p -> next = NULL;
    cout << "Item: ";
    cin >> p -> item;
    cout << "Cost: ";
    cin >> p -> cost;
    cout << "Retail: ";
    cin >> p -> retail;
    cout << "on_hand: ";
    cin >> p -> on_hand;
    cout << "Lead_time: ";
    cin >> p -> lead_time;

    //如果链表为空，加入第一个结点    *********必须加这一步，否则链表为空时，输入产品信息会出错
    if(tail == NULL)
        tail = p;
    //如果链表不为空，将新结点加到链表尾部
    else
        tail -> next = p;

    cout << endl;
    return pro;
}

//删除某个产品信息
inv *remove(inv *pro)
{
    //如果链表为空，输出提示信息
    if (pro == NULL)
    {
        cout << "Link is NULL" << endl << endl;
        return pro;
    }

    inv *p, *q;
    p = pro;
    q = pro -> next;
    char name[40];
    cout << "Please input the item you want to remove: ";
    cin >> name;
    cout << endl;
    //如果头结点为要删除的点，删除之
    if (!strcmp(name, pro -> item))
    {
        p = pro;
        pro = pro -> next;
        delete p;
        return pro;
    }
    //找到要删除结点
    while (q != NULL)
    {
        if (strcmp(name, q -> item))
        {
            p = q;
            q = q -> next;
        }
    }

    if (q != NULL)
    {
        p -> next = q -> next;
        delete q;
    }
    //如果未找到要删除的产品，输出提示信息
    else
        cout << "Item is not found!" << endl;

    cout << endl;
    return pro;
}

//更新某个产品信息
inv *update(inv *pro)
{
    //如果链表为空，输出提示信息
    if (pro == NULL)
    {
        cout << "Link is NLL!" << endl << endl;
        return pro;
    }

    inv *p;
    p = pro;
    char name[40];
    cout << "Please input the item you want to update: ";
    cin >> name;
    cout << endl;

    //找到要更新的产品
    while (p != NULL)
        p = p -> next;

    //如果未找到该产品，输出提示信息
    if (p == NULL)
    {
        cout << "Item is not found!" << endl << endl;
        return pro;
    }
    //更新产品信息
    cout << "Cost: ";
    cin >> p -> cost;
    cout << "Retail: ";
    cin >> p -> retail;
    cout << "on_hand: ";
    cin >> p -> on_hand;
    cout << "Lead_time: ";
    cin >> p -> lead_time;

    cout << endl;
    return pro;
}

//查看某种产品信息
void view(inv *pro)
{
    //如果链表为空，输出提示信息
    if (pro == NULL)
    {
        cout << "Link is NULL!" << endl << endl;
        return;
    }
    char name[40];
    cout << "Please input the item you want to view: ";
    cin >> name;
    cout << endl;

    inv *p;
    p = pro;

    //找到要查看的产品
    while (p != NULL)
        p = p -> next;

    //如果未找到该产品，输出提示信息
    if (p == NULL)
    {
        cout << "Item is not found!" << endl << endl;
        return;
    }
    //输出该产品信息
    cout << "Items: " << p -> item << endl;
    cout << "Cost: " << p -> cost << endl;
    cout << "Retail price: " << p -> retail << endl;
    cout << "On hand: " << p -> on_hand << endl;
    cout << "Lead time to resupply: " << p -> lead_time << endl;
    cout << endl;
}

int main()
{
    inv *product;
    product = new inv;
    product = NULL;

    //链表初始化
    product = creat();
    char choice;
    while (1)
    {
        //读入要进行的操作
        choice = manu();
        switch (choice)
        {
        case 'e':
            product = enter(product);
            break;
        case 'd':
            display(product);
            break;
        case 'r':
            product = remove(product);
            break;
        case 'u':
            product = update(product);
            break;
        case 'v':
            view(product);
            break;
        case 'q':
            return 0;
        }
    }
    return 0;
}