第39天

package 对象数组;

public class Student {
    private int id;
    private String name;
    private int age;

package 对象数组;

import java.util.Scanner;

public class StudentTest2 {
    public static void main(String[] args) {
        // 1、创建数组存储对象。
        Student[] s = new Student[3];
        Scanner sc = new Scanner(System.in);
        // 2、创建学生对象
        Student s1 = new Student(1, "cqz", 18);
        Student s2 = new Student(2, "xyq", 18);
        Student s3 = new Student(3, "qian", 20);
        // 3、学生对象存入数组
        s[0] = s1;
        s[1] = s2;
        s[2] = s3;
        // 查询id的学生，如果存在，他的年龄增加1；
        int flag = 0;
        int id = sc.nextInt();
        for (int i = 0; i < s.length; i++) {
            if (s[i] != null) {
                if (s[i].getId() == id) {
                    int age = s[i].getAge()+1;
                    s[i].setAge(age);
                    flag = 1;
                    break;
                }
            }
        }
        if (flag == 0) {
            System.out.println("不存在此ID.无法对年龄进行更改");
        }
        for (int i = 0; i < s.length; i++) {
            if (s[i] != null) {
                System.out.println(s[i].getId() + " " + s[i].getName() + " " + s[i].getAge());
            }
        }
    }
}

package 对象数组;

import java.util.Scanner;

public class StudentTest1 {
    public static void main(String[] args) {
        // 1、创建数组存储对象。
        Student[] s = new Student[3];
        Scanner sc = new Scanner(System.in);
        // 2、创建学生对象
        Student s1 = new Student(001, "cqz", 18);
        Student s2 = new Student(002, "xyq", 18);
        Student s3 = new Student(003, "qian", 20);
        // 3、学生对象存入数组
        s[0] = s1;
        s[1] = s2;
        s[2] = s3;
        //查询id的学生，如果相同，删除此人信息。
        int flag = 0;
        int id = sc.nextInt();
        for (int i = 0; i < s.length; i++) {
            if (s[i] != null) {
                if (s[i].getId() == id) {
                    s[i] = null;
                    flag = 1;
                    break;
                }
            }
        }
        if (flag == 0) {
            System.out.println("不存在此0ID.删除失败");
        }
        for (int i = 0; i < s.length; i++) {
            if (s[i] != null) {
                System.out.println(s[i].getId() + " " + s[i].getName() + " " + s[i].getAge());
            }
        }
        //查询id的学生，如果存在，他的年龄增加1；
        
    }
}

package 对象数组;

import java.util.Scanner;

public class StudentTest {
    public static void main(String[] args) {
        // 1、创建数组存储对象。
        Student[] s = new Student[3];
        Scanner sc = new Scanner(System.in);
        // 2、创建学生对象
        Student s1 = new Student(001, "cqz", 18);
        Student s2 = new Student(002, "xyq", 18);
        Student s3 = new Student(003, "qian", 20);
        // 3、学生对象存入数组
        s[0] = s1;
        s[1] = s2;
//        s[2] = s3;
        // 4、添加一个对象，添加时对学号唯一性进行判断
        Student s4 = new Student(001, "hebuyu", 18);
        // 对学号唯一性进行判断
        boolean flag = contains(s, s4.getId());
        if (flag) {
            System.out.println("此学号已经存在");
        } else {
            // 对学生数组长度进行判断
            int count = counts(s);
            // 如果没有存满
            if (count < s.length) {
                s[count] = s4;
                for (int i = 0; i < s.length; i++) {
                    if (s[i] != null) {
                        System.out.println(s[i].getId() + " " + s[i].getName() + " " + s[i].getAge());
                    }
                }
            }
            // 如果存满,创建一个新的数组.
            else {
                Student[] newS = createNewArr(s, count);
                newS[count] = s4;
                for (int i = 0; i < newS.length; i++) {
                    System.out.println(newS[i].getId() + " " + newS[i].getName() + " " + newS[i].getAge());
                }
            }
        }
    }

    public static Student[] createNewArr(Student s[], int count) {
        Student[] newS = new Student[count + 1];
        for (int i = 0; i < s.length; i++) {
            newS[i] = s[i];
        }
        return newS;
    }

    public static int counts(Student s[]) {
        int count = 0;
        for (int i = 0; i < s.length; i++) {
            if (s[i] != null) {
                count++;
            }
        }
        return count;
    }

    public static boolean contains(Student[] s, int id) {
        for (int i = 0; i < s.length; i++) {
            if (s[i] != null) {
                if (s[i].getId() == id) {
                    return true;
                }
            }
        }
        return false;
    }
}

 

public Student() {

    }

    public Student(int id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    public void setId(int id) {
        this.id = id;
    }

    public int getId() {
        return id;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public int getAge() {
        return age;
    }
}