数组代码和经典案例

  1 package Myhomework;
  2 /**
  3  * 学生管理系统
  4  */
  5 import javax.swing.JOptionPane;
  6 
  7 public class Myhomework11 {
  8     /** 学号数组 */
  9     public static int[] student = new int[1000];
 10     /** 姓名数组 */
 11     public static String[] name = new String[1000];
 12     /** 成绩数组 */
 13     public static int[] grade = new int[1000];
 14     public static int number = 0 ;
 15 
 16     public static void main(String[] args) {
 17         JOptionPane.showMessageDialog(null, "欢迎光临");
 18         boolean isLand = login();
 19         if (isLand == false) {
 20             JOptionPane.showMessageDialog(null, "非法用户");
 21             System.exit(0);
 22         }
 23     
 24     while(true){
 25         String s=JOptionPane.showInputDialog(null,"1、添加  2、显示 3、删除 4、查找 5、修改 6、排序 7、退出");
 26         int item=Integer.parseInt(s);
 27         switch(item){
 28         case(1):
 29         add();//添加
 30         break;
 31         case(2):
 32         show();//显示
 33         break;
 34         case(3):
 35         del();//删除
 36         break;
 37         case(4):
 38         find();//查找
 39         break;
 40         case(5):
 41         amend();//修改
 42         break;
 43         case(6):
 44         rank();//排序
 45         break;
 46         case(7):
 47         System.out.print("退出");//退出
 48         System.exit(0);
 49         }
 50         
 51     }
 52         
 53     }
 54     
 55     
 56     /**
 57      * 查找
 58      */
 59     public static void find() {
 60         int index = findName();
 61         if(index!=-1){
 62         JOptionPane.showMessageDialog(null,"学号为："+student[index]+" "+"姓名为："+name[index]+" "+"成绩为："+grade[index]);
 63         }
 64         }
 65     /**
 66      * 删除
 67      */
 68     public static void del(){
 69         int index = findName();
 70         if(index!=-1){
 71         for(int i = index ; i < number ; i++){
 72         student[i] = student[i+1];
 73         name[i] = name[i+1];
 74         grade[i] = grade[i+1];
 75 
 76         }
 77         number--;
 78         show();
 79         }
 80     }
 81     /**
 82      * 修改
 83      */
 84     
 85     public static void amend(){
 86         int index = findName();
 87         if(index!=-1){
 88         String newstudent = JOptionPane.showInputDialog(null,"请重新输入学号");
 89         String newname = JOptionPane.showInputDialog(null,"请重新输入姓名");
 90         String newgrade = JOptionPane.showInputDialog(null,"请重新输入成绩");
 91         student[index] = Integer.parseInt(newstudent);
 92         name[index] = newname;
 93         grade[index] = Integer.parseInt(newgrade);
 94         show();
 95         }
 96     }
 97     /**
 98      * 排序
 99      */
100     
101     public static void rank(){
102         for(int i = 0; i < number; i++){
103             for(int j = i+1; j < number; j++){
104             if(grade[i]<grade[j]){
105             int num1 = student[i];
106             student[i] = student[j];
107             student[j] = num1;
108             String num2 = name[i];
109             name[i] = name[j];
110             name[j] = num2;
111             int num3 = grade[i];
112             grade[i] = grade[j];
113             grade[j] = num3;
114             }
115             }
116         }
117             show();
118     }
119     /**
120      * 显示
121      */
122     public static void show(){
123         String str="学号  姓名  成绩\n";
124         for(int i=0;i<number;i++){
125         str +=student[i]+"     "+name[i]+"    "+grade[i]+"\n";
126         }
127         JOptionPane.showMessageDialog(null, str);
128     }
129     /**
130      * 添加
131      */
132     public static void add(){
133     String student1 =JOptionPane.showInputDialog(null,"请添加学号");
134     String name1=JOptionPane.showInputDialog(null,"请输入姓名");
135     String grade1=JOptionPane.showInputDialog(null,"请输入成绩");
136     student[number]=Integer.parseInt(student1);
137     name[number]=name1;
138     grade[number]=Integer.parseInt(grade1);
139     number++;
140     }
141     /**
142      * 登录
143      * @return 登录是否成功
144      */
145     
146     public static boolean login(){
147         for(int i=0;i<3;i++){
148     String code=JOptionPane.showInputDialog(null,"请输入用户名");
149     String pwd=JOptionPane.showInputDialog(null,"请输入密码");
150     if(code.equals("张二狗")&&(pwd.equals("123456"))){
151         return true;
152     }else{
153         JOptionPane.showMessageDialog(null, "用户名或密码错误");
154         if(i<=1){
155         JOptionPane.showMessageDialog(null, "你还有"+(2-i)+"次机会");
156     }else{
157         JOptionPane.showMessageDialog(null, "你已经连续三次输错，已无机会");
158     }
159     }    
160         }
161         return false;
162         
163     }
164     /**
165      * 寻找姓名在该姓名下的下标，如果没有找到返回-1
166      * @param name 
167      * 
168      * @return 姓名对应的下标
169      */
170 
171 public static int findName(){
172     String nameStr = JOptionPane.showInputDialog(null,"请输入姓名");
173     for(int i = 0 ; i <number;i++ ){
174     if(nameStr.equals(name[i])){
175     return i;
176     }
177     }
178     JOptionPane.showMessageDialog(null,"查无此人");
179     return-1;
180     }
181 }