1 package Student_Manage;  2 import javax.swing.JOptionPane;  3   4 public class Manage_NOTUseClass {  5       6       7     public static String [] name = new String [20];//学生姓名数组  8     public static int [] card = new int [20];//学生学号数组  9     public static int [] score = new int [20]; //学生成绩数组 10     public static int number = 0;//学生数目 11      12     public static void main(String[] args) { 13         // 学生管理系统 14         //要求实现登陆，学生信息的添加、显示， 删除，修改，查询，排序，退出功能 15         /**欢迎光临界面*/ 16         JOptionPane.showMessageDialog(null, "欢迎光临！"); 17          18         /**登陆用户名、密码验证*/ 19         String user = "111" ; 20         String pwd = "222"; 21         for (int i = 0;i<3 ; i++){ 22             String in_user = JOptionPane.showInputDialog(null , "用户名："); 23             String in_pwd = JOptionPane.showInputDialog(null , "密码："); 24             if ( in_user.equals(user) && in_pwd.equals(pwd)){//判定用户名和密码是否正确 25                 break ; 26             }else { 27                 JOptionPane.showMessageDialog(null, "用户名或密码错误！"); 28                 if (i==2){ 29                     JOptionPane.showMessageDialog(null, "非法用户！"); 30                     System.exit(0); 31                 } 32             } 33         } 34          35         /**菜单选项*/ 36         while (true){ 37             int choose_num = Integer.parseInt(JOptionPane.showInputDialog(null , "1、添加\n2、显示\n3、删除\n4、修改\n5、查询\n6、排序\n7、退出")); 38             switch (choose_num){ 39                 case 1 :  40                     add() ;  41                     break ; 42                 case 2 :  43                     show();  44                     break ; 45                 case 3 :  46                     del() ;  47                     break ; 48                 case 4 :  49                     repair();  50                     break ; 51                 case 5 :  52                     check();  53                     break ; 54                 case 6 :  55                     sort();  56                     break ; 57                 case 7 :  58                     JOptionPane.showMessageDialog(null, "系统已退出！"); 59                     System.exit(0); 60                     break ; 61                 default : JOptionPane.showMessageDialog(null, "无此选项，请重新选择！");break ; 62             } 63         } 64     } 65     /**添加一个学生*/ 66     public static void add(){ 67         name [number] = JOptionPane.showInputDialog(null , "请输入姓名："); 68         card [number] = Integer.parseInt(JOptionPane.showInputDialog(null, "请输入学号：")); 69         score [number] = Integer.parseInt(JOptionPane.showInputDialog(null, "请输入成绩：")); 70         number ++; 71     } 72     /**排序*/ 73     public static void sort() { 74             for (int i =0;i < number ; i++){ 75                 for (int j = i; j<number;j++){ 76                     int temp = 0 ; 77                     String s = ""; 78                     if (score [i] < score [j]){ 79                         s = name [i] ; 80                         name [i]  = name [j] ; 81                         name[j] = s ; 82                          83                         temp = card [i] ; 84                         card [i]   = card [j]  ; 85                         card [j]  = temp ; 86                          87                         temp = score[i] ; 88                         score [i]   = score [j]  ; 89                         score [j]  = temp ; 90                     } 91                 } 92             } 93             JOptionPane.showMessageDialog(null, "排序成功！");     94     } 95     /**显示*/ 96     public static void show(){ 97         String s = "学号"+"    "+"姓名"+"    "+"成绩"+"\n"; 98         for (int i = 0 ;i< number ;i++){ 99             s+=card [i] + "    "+ name [i]+"    "+ score [i]+"\n";100         }101         JOptionPane.showMessageDialog(null, s);102     }103     /**删除*/104     public static void del(){105         int index = findByName();106         if (index !=-1){107             //方法一：将最后位置的一个元素放在被删除元素的位置108 //        name [index] = name[ number-1];109 //        card [index] =card[ number-1];110 //        score [index] = score[ number-1];111 //        number--;112             //方法二 ：连续将后一个元素填补至前一个元素113             for (int i = index; i <number ; i++){114                 name [i] = name [i+1];115                 card [i] = card [i+1];116                 score [i] = score [i+1] ;117             }118             number--;119         JOptionPane.showMessageDialog(null, "删除成功！");    120         }121     }122     /**修改*/123     public static void repair(){124         int index = findByName();125         if (index !=-1){126             name [index] =JOptionPane.showInputDialog(null , "请输入新的名字：");127             card [index] = Integer.parseInt(JOptionPane.showInputDialog(null , "请输入该学生的学号"));128             score [index] = Integer.parseInt(JOptionPane.showInputDialog(null , "请输入该学生的成绩"));129             JOptionPane.showMessageDialog(null, "修改成功！");130         }131     }132     /**查询*/133     public static void check(){134         int index  =findByName();135         if (index !=-1){136         JOptionPane.showMessageDialog(null,name[index]+"\n学号：" +card[index]+"\n成绩："+score [index]);137         }138     }139     /**代码重用---查找*/140     public static int findByName (){141         int index = -1 ;142         String check_name = JOptionPane.showInputDialog(null,"请输入要查询的名字：");143         for (int i = 0; i< number ;i++){144             if (check_name.equals(name [i])){145                 return i ;146             }147         }148         if (index == -1){149             JOptionPane.showMessageDialog(null, "查无此人！");150         }151         return index ;152     }153 }