超市管理系统简易版

import java.util.ArrayList;
import java.util.Scanner;

public class Shopp {
    
    public static void mainMenu()//菜单
    {
        System.out.println("==============欢迎光临超市==============");
        System.out.println("1:货物清单"+ " " + "2:添加新货物" + " " + "3:删除货物" + "4:修改货物" + "5:退出系统");
        System.out.println("请输入要操作的功能序号");
    }
    public static void init(ArrayList<FruitItem> array)//超市商品初始化
    {
        FruitItem fi1= new FruitItem();
        fi1.ID = 10;
        fi1.name = "小鸡腿";
        fi1.price = 3;
        FruitItem fi2= new FruitItem();
        fi2.ID = 11;
        fi2.name = "老干妈";
        fi2.price = 13.5;
        FruitItem fi3= new FruitItem();
        fi3.ID = 12;
        fi3.name = "王老吉";
        fi3.price = 4;
        array.add(fi1);
        array.add(fi2);
        array.add(fi3);
    }
    public static void showFruitList(ArrayList<FruitItem> array)//库存货物查询
    {
        System.out.println();
        System.out.println("============商品清单============");
        System.out.println("商品编号"+ "  "+"商品名称" + "  "+"商品单价");
        for(int i = 0; i < array.size(); i++)
        {
            FruitItem fi = array.get(i);
            System.out.println(fi.ID + "    "+ fi.name + "       "+fi.price);
        }
        
    }
    //添加新货物
    public static void addFruitItem(ArrayList<FruitItem> array)
    {
        FruitItem fi = new FruitItem();
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入新的商品编号");
        fi.ID = sc.nextInt();
        System.out.println("请输入新的商品名称");
        fi.name = sc.next();
        System.out.println("输入新商品的价格");
        fi.price = sc.nextDouble();
        array.add(fi);
    }
    public static void delFruitItem(ArrayList<FruitItem> array)//删除商品
    {
        System.out.println("选择的是删除商品功能");
        System.out.println("请输入商品编号");
        Scanner sc = new Scanner(System.in);
        int ID = sc.nextInt();
        for(int i = 0; i < array.size(); i++)
        {
            FruitItem fi = array.get(i);
            if(fi.ID == ID)
            {
                array.remove(i);
                System.out.println("删除成功");
                return;//当fi.ID == ID时，就删除了，没必要再循环比下去了，直接结束return
            }
        }
        System.out.println("未找到该商品！");
    }
    public static void updateFruitItem(ArrayList<FruitItem> array)
    {
        System.out.println("这是修改功能");
        System.out.println("请输入需要修改的商品编号");
        Scanner sc = new Scanner(System.in);
        int ID = sc.nextInt();
        System.out.println("您修改的商品编号为：" + ID);
        for(int i = 0; i < array.size();i++)
        {
            if(array.get(i).ID == ID)
            {
                System.out.println("请输入新的商品编号");
                array.get(i).ID = sc.nextInt();
                System.out.println("请输入新的商品名称");
                array.get(i).name = sc.next();
                System.out.append("请输入新的商品单价");
                array.get(i).price = sc.nextDouble();
                System.out.println("修改成功");
                return;//当编号相等，改商品数据成功后，没必要继续执行下面的输出语句
            }
        }
        System.out.println("您输入的编号不存在");
    }
    
    public static void main(String[] args) {
        ArrayList<FruitItem> array = new ArrayList<FruitItem>();
        init(array);
        Scanner sc = new Scanner(System.in);
        
        while(true)//死循环，一定要保证循环条件有变成false的时候
        {
            mainMenu();
            int i = sc.nextInt();
            switch(i)
            {
            case 1:
                showFruitList(array);//货物清单
                break;
            case 2:
                addFruitItem(array);//添加新货物
                break;
            case 3:
                delFruitItem(array);//删除商品
            break;
            case 4:
            updateFruitItem(array);//修改商品
            break;
            case 5:
            System.out.println("退出系统");
            return;
            default:
            System.out.println("暂无此功能");
            break;    
        }
        
    }
    }
}