String&Array字符串|数组练习

Posted 2023-02-20 Richard_i

String&Array

• 练习
• 关于String类的方法和Array的操作
• 字符串分割，数组排序，字符串赋值给自定义对象并添加到数组中

题目：

1. 从键盘上输入身份证号, 判断出生日期,性别，
   身份证倒数第二位表示性别，双数为女性，单为男

2. 有字符串: ”101,lisi,98;

   202,wangwu,76;

   303,chenqi,84;

   404,zhangsan,49;

   505,xiaoming,67”,

   保存的学生的学号,姓名,成绩信息.

   要求把字符串中学生信息取出来,创建Student对象,

   把Student对象保存到数组中;遍历学生对象数组;

   在数组中查找名字为xiaoxiao同学是否存在.对数组中学生对象根据成绩降序排序

---

import java.util.Scanner;

/**
 * @ClassName Judge
 * @Deacription TODO 1. 从键盘上输入身份证号, 判断出生日期,性别
 *                   2. 身份证倒数第二位表示性别，双数为女性，单为男
 * @Version 1.0
 */
public class Judge 
    public static void main(String[] args) 
        Scanner sc = new Scanner(System.in);
        boolean verify = true;
        while (verify)
            System.out.print("请输入你的身份证号码:");
            String id = sc.next();
            // 用正则表达验证控制台输入
            boolean control = id.matches("\\\\d17(\\\\d|X|x)");
            if (control)
                // 截取身份证中出生日期
                String birth = id.substring(6, 14);
                // 取出倒数第二位的元素，偶数为女性
                char c = id.charAt(id.length() - 2);
                if (c % 2 == 0)
                    System.out.println("女性\\t" + "出生日期：" + birth);
                    // 判断成功结束
                    verify = false;
                else 
                    System.out.println("男性\\t" + "出生日期：" + birth);
                    verify = false;
                
            else
                //不合法继续循环
                System.out.println("身份证输入不合法...请重新输入！");
            
        
    

Student类

public class Student implements Comparable<Student>
    private String id;
    private String name;
    private String score;

    public Student(String id, String name, String score) 
        this.id = id;
        this.name = name;
        this.score = score;
    
    public Student() 
    

    public String getId() 
        return id;
    

    public Student setId(String id) 
        this.id = id;
        return this;
    

    public String getName() 
        return name;
    

    public Student setName(String name) 
        this.name = name;
        return this;
    

    public String getScore() 
        return score;
    

    public Student setScore(String score) 
        this.score = score;
        return this;
    

    @Override
    public String toString() 
        return "Student" +
                "id='" + id + '\\'' +
                ", name='" + name + '\\'' +
                ", score='" + score + '\\'' +
                '';
    

    @Override
    public int compareTo(Student o) 
        return o.getScore().compareTo(this.getScore());
    

测试类

/**
 * @ClassName StudentTest
 * @Deacription
 *  TODO
 *     有字符串: ”101,lisi,98;
 *              202,wangwu,76;
 *              303,chenqi,84;
 *              404,zhangsan,49;
 *              505,xiaoming,67”,
 *      保存的学生的学号,姓名,成绩信息.
 *      要求把字符串中学生信息取出来,创建Student对象,
 *      把Student对象保存到数组中;遍历学生对象数组;
 *      在数组中查找名字为xiaoxiao同学是否存在.对数组中学生对象根据成绩降序排序
 * @Version 1.0
 */
public class StudentTest 
    public static void main(String[] args) 
        String src = "101,lisi,98;202,wangwu,76;303,chenqi,84;404,zhangsan,49;505,xiaoming,67";
        // 分号替换成逗号
        String replace = src.replace(";", ",");
        // 通过逗号分隔字符串
        String[] split = replace.split(",");
        for (String s : split) 
            System.out.print(s + " ");
        
        //创建学生数组
        Student[] stus = new Student[5];
        // 思路，内循环，分隔字符串后并按照每3个字符分别赋值给不同的对象
        // split[i]元素下标为持续+1，定义初始值，循环自增
        int index = 0;
        for (int i = 0; i < stus.length ; i++) 
                String id = split[index++];
                String name = split[index++];
                String score = split[index++];
                Student student = new Student(id,name,score);
                stus[i] = student;
        
        System.out.println();
        // 遍历学生对象，未排序
        for (Student student : stus) 
            System.out.println(student);
        
//        对自定义类型进行排序需要实现Comparable并实现CompareTo方法重写规则
//        否则报错Exception in thread "main" java.lang.ClassCastException
        Arrays.sort(stus); // sort默认升序，已在Student类重新编写排序规则
        //判断学生是否存在
        if (isExist1(stus,"xiaoxiao"))
            System.out.println("学生存在");
        else
            System.out.println("不存在");
        
        // 按照成绩降序输出
        System.out.println("按照学生成绩降序输出");
        for (Student student : stus) 
            System.out.println(student);
        
    

    public static boolean isExist1(Student[] stus ,String target)
        for (int i = 0; i < stus.length; i++) 
            if (target.equals(stus[i].getName()))
                return true;
            
        
        return false;