Java对象数组练习
Student类
package Student.com;
/**
* 学生类
* @author Strive
*/
public class Student {
private int id;
private String name;
private double score;
public Student() {}
public Student(int id, String name, double score) {
this.id = id;
this.name = name;
this.score = score;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getScore() {
return score;
}
public void setScore(double score) {
this.score = score;
}
}
StudentManager
package Student.com;
public class StudentManager {
private int index = 1;
private int count = 0;
private Student[] student;
//ID
public int getStudentId() {
return index++;
}
public StudentManager() {
student = new Student[100];
String[] name = {"张三","李四","王五","张明","比尔盖茨","礼记","二狗"};
double[] score = {70,68,58,98,86,74,94};
for (int i = 0; i < student.length; i++) {
if (student[i] == null) {
if (i == 7) {
break;
}
student[i] = new Student(getStudentId(),name[i],score[i]);
count++;
}
}
}
/**
* 查询所有学生
* @return 学生数组
*/
public Student[] list() {
Student[] stu = new Student[count];
for (int i = 0,len = student.length; i < len; i++) {
if (student[i] != null) {
stu[i] = student[i];
}
}
return stu;
}
/**
* 添加学生
* @param stu 学生对象
* @return 是否成功
*/
public boolean addStudent(Student stu) {
boolean flag = false;
for (int i = 0,len = student.length; i < len; i++) {
if (student[i] == null) {
stu.setId(getStudentId());
stu.setName(stu.getName());
stu.setScore(stu.getScore());
student[i] = stu;
count++;
flag = true;
break;
}
}
return flag;
}
public boolean removeStudent(int id) {
int index = 0;
boolean flag = false;
for (int i = 0,len = student.length - 1; i < len; i++) {
if (student[i] == null) {
break;
}
if (student[i].getId() == id) {
count--;
index = i;
flag = true;
break;
}
}
for (int i = index; i < student.length - 1; i++) {
student[i] = student[i + 1];
}
student[student.length - 1] = null;
return flag;
}
public boolean updateStudent(Student s) {
boolean flag = false;
for (int i = 0,len = student.length; i < len; i++) {
if (student[i] == null) {
break;
}
if (student[i].getId() == s.getId()) {
student[i].setName(s.getName());
student[i].setScore(s.getScore());
flag = true;
break;
}
}
return flag;
}
}
Test
package Student.com;
import java.util.Scanner;
/**
* 测试类
* @author Strive
*/
public class Test {
private Scanner input = new Scanner(System.in);
private StudentManager mana = new StudentManager();
public static void main(String[] args) {
new Test().Menu();
}
public void Menu() {
do {
System.out.println("-----------------欢迎使用学生管理系统!-----------------");
System.out.println("1.查看学生");
System.out.println("2.删除学生");
System.out.println("3.更新学生");
System.out.println("4.搜索学生");
System.out.println("5.添加学生");
System.out.println("6.排序");
System.out.println("请输入操作符：");
String key = input.next();
switch (key) {
case "1":
all();
break;
case "2":
delete();
break;
case "3":
update();
break;
case "4":
search();
break;
case "5":
add();
break;
case "6":
sort();
break;
default:
System.out.println("输出错误！");
continue;
}
break;
} while(true);
}
public void all() {
Student[] list = mana.list();
System.out.println("id\t姓名\t成绩");
if (list.length != 0) {
for (Student li : list) {
System.out.println(li.getId() + "\t" + li.getName() + "\t" + li.getScore());
}
} else {
System.out.println("没有更多数据!");
}
next();
}
public void add() {
do {
Student stu = new Student();
System.out.println("请输入姓名：");
String name = input.next();
if (existsStudentName(name)) {
System.out.println("学生姓名已存在!");
continue;
}
double score = 0;
System.out.println("请输入成绩：");
try {
score =input.nextDouble();
}catch(Exception e) {
System.out.println("只能输入数字！");
continue;
}
stu.setName(name);
stu.setScore(score);
System.out.println(mana.addStudent(stu) == true ? "添加学生\""+name+"\"成功！" : "添加学生\""+name+"\"失败！");
next();
break;
} while(true);
}
public boolean existsStudentName(String name) {
Student[] list = mana.list();
for (int i = 0,len = list.length; i < len; i++) {
if (list[i].getName().equals(name)) {
return true;
}
}
return false;
}
public void update() {
System.out.println("请输入学生id:");
int id = input.nextInt();
System.out.println("请输入学生姓名:");
String name = input.next();
System.out.println("请输入学生成绩:");
double score = input.nextDouble();
Student stu = new Student(id,name,score);
System.out.println(mana.updateStudent(stu) == true ? "更新成功！" : "更新失败！");
next();
}
public void search() {
System.out.println("请输入学生姓名：");
String name = input.next();
Student[] list = mana.list();
for (int i = 0; i < list.length; i++) {
if (list[i].getName().equals(name)) {
System.out.println(list[i].getId() + "\t" + list[i].getName() + "\t" + list[i].getScore());
}
}
next();
}
public void delete() {
System.out.println("请输入学生id:");
int id = input.nextInt();
boolean flag = mana.removeStudent(id);
System.out.println(flag == true ? "删除成功！" : "删除失败！");
next();
}
public void sort() {
Student[] list = mana.list();
Student student;
for (int i = 0; i < list.length; i++) {
for (int j = 0; j < i; j++) {
if (list[i].getScore() > list[j].getScore()) {
student = list[i];
list[i] = list[j];
list[j] = student;
}
}
}
for (Student li : list) {
System.out.println(li.getId() + "\t" + li.getName() + "\t" + li.getScore());
}
next();
}
public void next() {
do {
System.out.println("按e返回:");
String name = input.next();
if (name.equals("e")) {
Menu();
} else {
continue;
}
} while(true);
}
}
