java 用集合完成随机点名器和库存管理案例

import java.util.*;
class  Demo02
{
    public static void main(String[] args) 
    {    //储存全体学生的信息
        ArrayList<String> stuname = new ArrayList<String>();
        stuname.add("姓名：张三,年龄：99");
        stuname.add("姓名：李四,年龄：100");
        stuname.add("姓名：王五,年龄：77");
        stuname.add("姓名：赵六,年龄：50");
        stuname.add("姓名：孙七,年龄：60");
        //总览全体同学信息
        for (int i = 0;i<stuname.size() ;i++ ){
            System.out.print(stuname.get(i)+"  ");
        }
        System.out.println();
        //随机点名
        Random ra = new Random();
        int r = ra.nextInt(stuname.size());
        System.out.println(stuname.get(r));
    }
}

import java.io.*;
import java.util.Scanner;
import java.util.ArrayList;
class HomeWork0630 
{
    public static void main(String[] args)throws IOException
    {
        menu();
    }
    public static void show(){
        System.out.println("------库存管理------");
        System.out.println("1.查看库存清单");
        System.out.println("2.修改商品库存数量");
        System.out.println("3.退出");
        System.out.println("请输入要执行的操作序号：");
    }
    public static void menu()throws IOException{
        Scanner sc = new Scanner(System.in);
        ArrayList<String> brand =new ArrayList<String>();
        ArrayList<Double> sizee =new ArrayList<Double>();
        ArrayList<Double> price =new ArrayList<Double>();
        ArrayList<Integer> num =new ArrayList<Integer>();
        brand.add("MacBookAir");
        brand.add("ThinkpadT450");
        brand.add("ASUS-FL5800");
        sizee.add(13.3);
        sizee.add(14.0);
        sizee.add(15.6);
        price.add(6988.88);
        price.add(5999.99);
        price.add(4999.5);
        num.add(5);
        num.add(10);
        num.add(18);
        while(true){
        show();
        int s = sc.nextInt();
        switch(s){
            case 1:
                look(brand,sizee,price,num);
                break;
            case 2:
                change(brand,num);
                break;
            case 3:
                return;
            default:
                System.out.println("输入有误请重新输入！");
        }
        }
    }
    public static void look(ArrayList<String> brand,ArrayList<Double> sizee,ArrayList<Double> price,
        ArrayList<Integer> num)throws IOException{
            System.out.println("----------商城库存清单----------");
            System.out.println("品牌型号\t尺寸\t价格\t库存数");
            for (int i=0;i<brand.size() ;i++ ){
                System.out.println(brand.get(i)+"\t"+sizee.get(i)+"\t"+price.get(i)+"\t"+num.get(i));
            }
            System.out.println("--------------------------------");
            int sum = 0;
            for (int i = 0;i<brand.size() ;i++ ){
                sum+=num.get(i);
            }
            System.out.println("总库存数："+sum);
            double sum2 = 0;
            for (int i = 0;i<brand.size() ;i++ ){
                sum2+=num.get(i)*price.get(i);
            }
            System.out.println("库存商品总金额："+sum2);
            System.out.println("输入回车键返回主菜单");         
            if(new InputStreamReader(System.in).read() == 13){
                return;
            }
        }
        public static void change(ArrayList<String> brand,ArrayList<Integer> num){    
                Scanner sca = new Scanner(System.in);
                while(true){
                System.out.println("-------------库存表-------------");
                System.out.println("序号\t品牌型号\t库存数");
                for (int i=0;i<brand.size() ;i++ ){
                    System.out.println(i+1+"\t"+brand.get(i)+"\t"+num.get(i));
                }
                System.out.println("--------------------------------");
                System.out.println("请根据上表输入需要改库存商品的序号，按0返回主界面：");    
                int s = sca.nextInt();
                int num1=0;
                    if ((s-1)<brand.size()&&s>0){
                        System.out.println("请输入修改后的内存数：");
                        num1=sca.nextInt();
                        num.set(s-1,num1);
                        System.out.println("修改成功！结果为：");
                        System.out.println("-------------库存表-------------");
                        System.out.println("序号\t品牌型号\t库存数");
                        for (int i=0;i<brand.size() ;i++ ){
                        System.out.println(i+1+"\t"+brand.get(i)+"\t"+num.get(i));
                          }
                        System.out.println("--------------------------------");
                        while(true){
                            System.out.println("是否继续修改：按1继续,按0返回主菜单");
                            int b = sca.nextInt();                            
                            if (b==1){
                                break;
                            }else if(b==0){
                                return;
                            }else{
                                System.out.println("您的输入有误请重新输入！");    
                            }
                        }
                    }else if(s==0){
                        return;
                    }else{
                        System.out.println("您的输入有误请重新输入！");        
                    }
                }        
        }
}