学生管理系统

import javax.swing.JOptionPane;

public class HomeWork_13_Working {

    public static int numArray[] = new int[20];

    public static String nameArray[] = new String[20];

    public static int gradeArray[] = new int[20];

    public static int number = 0;

    public static void main(String[] args) {

        JOptionPane.showMessageDialog(null, "欢迎使用学生查询系统！");

        String user = "fj";

        String pwd = "1";

        boolean islogin = login(user, pwd);

        if (islogin == true) {

            for (;;) {

                String fuction = JOptionPane.showInputDialog(null, "1、添加" + "\n" + "2、显示" + "\n" + "3、删除" + "\n"

                        + "4、查找" + "\n" + "5、修改" + "\n" + "6、排序" + "\n" + "7、退出" + "\n");

                int t = Integer.parseInt(fuction);

                switch (t) {

                case 1:

                    add();

                    break;

                case 2:

                    show();

                    break;

                case 3:

                    del();

                    break;

                case 4:

                    find();

                    break;

                case 5:

                    amend();

                    break;

                case 6:

                    sort();

                    break;

                case 7:

                    System.exit(0);

                }

            }

        }

    }

    // 酷查下标

    public static int coolfind() {

        String name = JOptionPane.showInputDialog(null, "请输入姓名");

        int index = -1;

        for (int i = 0; i < nameArray.length; i++) {

            if (name.equals(nameArray[i])) {

                index = i;

                break;

            }

        }

        return index;

    }

    // 排序

    public static void sort() {

        for (int i = 0; i < gradeArray.length; i++) {

            for (int j = i + 1; j < gradeArray.length; j++) {

                if (gradeArray[i] < gradeArray[j]) {

                    int t = gradeArray[i];

                    gradeArray[i] = gradeArray[j];

                    gradeArray[j] = t;

                    String s = nameArray[i];

                    nameArray[i] = nameArray[j];

                    nameArray[j] = s;

                    int x = numArray[i];

                    numArray[i] = numArray[j];

                    numArray[j] = x;

                }

            }

        }

        show();

    }

    // 修改

    public static void amend() {

        int index = coolfind();

        if (index != -1) {

            String num = JOptionPane.showInputDialog(null, "请输入新学号");

            String name = JOptionPane.showInputDialog(null, "请输入新姓名");

            String grade = JOptionPane.showInputDialog(null, "请输入新成绩");

            numArray[index] = Integer.parseInt(num);

            nameArray[index] = name;

            gradeArray[index] = Integer.parseInt(grade);

            show();

        } else {

            JOptionPane.showMessageDialog(null, "查无此人");

        }

    }

    // 查找

    public static void find() {

        int index = coolfind();

        if (index == -1) {

            JOptionPane.showMessageDialog(null, "查无此人！");

        } else {

            JOptionPane.showMessageDialog(null,

                    "学号:" + numArray[index] + "  姓名:" + nameArray[index] + "  成绩：" + gradeArray[index]);

        }

    }

    // 删除

    public static void del() {

        int index = coolfind();

        if (index != -1) {

            for (int i = index; i < number; i++) {

                numArray[i] = numArray[i + 1];

                nameArray[i] = nameArray[i + 1];

                gradeArray[i] = gradeArray[i + 1];

            }

            number--;

            show();

        } else {

            JOptionPane.showMessageDialog(null, "查无此人");

        }

    }

    // 显示

    public static void show() {

        String str = "学号" + "  " + "姓名" + "  " + "分数" + "  " + "\n";

        for (int i = 0; i < number; i++) {

            str += numArray[i] + "        " + nameArray[i] + "    " + gradeArray[i] + "\n";

        }

        JOptionPane.showMessageDialog(null, str);

    }

    // 登录

    public static boolean login(String user, String pwd) {

        for (int i = 3; i > 0; i--) {

            String user1 = JOptionPane.showInputDialog(null, "请输入用户名");

            String pwd1 = JOptionPane.showInputDialog(null, "请输入密码");

            if (user1.equals(user) && pwd1.equals(pwd)) {

                JOptionPane.showMessageDialog(null, "登录成功！");

                return true;

            } else {

                if (i == 1) {

                    JOptionPane.showMessageDialog(null, "非法用户！");

                    System.exit(0);

                }

                JOptionPane.showMessageDialog(null, "用户名或密码错误");

            }

        }

        return false;

    }

    // 添加

    public static void add() {

        String numArray1 = JOptionPane.showInputDialog(null, "请输入学号");

        String nameArray1 = JOptionPane.showInputDialog(null, "请输入姓名");

        String gradeArray1 = JOptionPane.showInputDialog(null, "请输入成绩");

        numArray[number] = Integer.parseInt(numArray1);

        nameArray[number] = nameArray1;

        gradeArray[number] = Integer.parseInt(gradeArray1);

        number++;

    }

}