开发环境: Windows 11 IDEA 2021.3.3
需求:
package com.it.neu;
import java.util.ArrayList;
import java.util.Scanner;
import static java.time.Clock.system;
class Student { //创建学生类
private String Stu_name;
private String Stu_id;
public Student(String id, String name) {
this.Stu_id = id;
this.Stu_name = name;
}
public String getStu_name() {
return Stu_name;
}
public void setStu_name(String stu_name) {
Stu_name = stu_name;
}
public String getStu_id() {
return Stu_id;
}
public void setStu_id(String stu_id) {
Stu_id = stu_id;
}
}
class Course { //创建课程类
private String Course_name;
public Course(String course_name) {
this.Course_name = course_name;
}
public String getCourse_name() {
return Course_name;
}
public void setCourse_name(String course_name) {
Course_name = course_name;
}
}
class Score { //创建成绩表类
private int rank; //序号--代表进入成绩管理系统的位次
private Student student;
private Course course;
private double grade; //代表成绩的意思
public Score(int rank, Student student, Course course, double grade) {
this.rank = rank;
this.student = student;
this.course = course;
this.grade = grade;
}
public int getRank() {
return rank;
}
public void setRank(int rank) {
this.rank = rank;
}
public Student getStudent() {
return student;
}
public void setStudent(Student student) {
this.student = student;
}
public Course getCourse() {
return course;
}
public void setCourse(Course course) {
this.course = course;
}
public double getGrade() {
return grade;
}
public void setGrade(double grade) {
this.grade = grade;
}
}
class StudentScoreManager { //创建一个成绩管理的类
private ArrayList<Score> scores;//新建一个类的数组
public StudentScoreManager() {
scores = new ArrayList<>();
} //初始化这个类成员数组
//通过调用manager.addScore(score)方法，将score对象添加到scores列表中。
// 如果这个方法成功执行并返回true，那么score对象就会被添加到scores列表中。
public boolean addScore(Score score) {
return scores.add(score); // 将score对象添加到列表中，并返回添加操作的结果
}
//删除学生成绩的功能，某一门课//同时判断是否删除成功
public boolean removeScore(Student student, Course course) {
for (Score score : scores) {
if (score.getStudent().getStu_id().equals(student.getStu_id()) && score.getStudent().getStu_name().equals(student.getStu_name()) && score.getCourse().getCourse_name().equals(course.getCourse_name())) {
scores.remove(score);
return true;
}
}
return false;
}
//实现修改成学生成绩功能
public boolean changeScore(Student student, Course course, double newGrade) {
for (Score score : scores) {
if (score.getStudent().getStu_id().equals(student.getStu_id()) && score.getStudent().getStu_name().equals(student.getStu_name()) && score.getCourse().getCourse_name().equals(course.getCourse_name())) {
score.setGrade(newGrade);
return true;
}
}
return false;
}
//实现计算某门课平均成绩的功能
public double getAverageGrade(Course course) {
double sum = 0;
int count = 0;
for (Score score : scores) {
if (score.getCourse().getCourse_name().equals(course.getCourse_name())) { //找到这门课了
sum += score.getGrade();
count++;
}
}
return count > 0 ? sum / count : 0;
}
//查找某门课的最高成绩
public double getHighesrGrade(Course course) { //某门课的最高成绩
double higest = 0;
for (Score score : scores) {
if (score.getCourse().getCourse_name().equals(course.getCourse_name()) && score.getGrade() > higest) {
higest = score.getGrade();
}
}
return higest;
}
//查找某门课的最低成绩
public double getLowestGrade(Course course) {
double lowest = 100;
for (Score score : scores) {
if (score.getCourse().getCourse_name().equals(course.getCourse_name()) && score.getGrade() < lowest) {
lowest = score.getGrade();
}
}
return lowest;
}
//实现成绩排序功能
public void sortScores() {
scores.sort((s1, s2) -> Double.compare(s2.getGrade(), s1.getGrade()));
}
public void printScores() {
sortScores();
for (Score score : scores) {
System.out.println(score.getRank() + " " + score.getStudent().getStu_id() + " " + score.getStudent().getStu_name() + " " + score.getCourse().getCourse_name() + " " + score.getGrade());
}
}
public boolean printfixScores(Student student) {
int count = 0;
for (Score score : scores) {
if (score.getStudent().getStu_id().equals(student.getStu_id()) && score.getStudent().getStu_name().equals(student.getStu_name())) {
System.out.println(score.getCourse().getCourse_name() + "的成绩是" + score.getGrade());
count++;
}
}
return count > 0 ? true : false;
}
//获取scores类list的长度
public int getScoresLength() {
return scores.size();
}
}
public class Work {
public static void printmenu() {
System.out.println("---------------------------------------");
System.out.println("欢迎使用学生成绩管理系统");
System.out.println("---------------------------------------");
System.out.println("1. 添加学生成绩");
System.out.println("2. 删除学生成绩");
System.out.println("3. 修改学生成绩");
System.out.println("4. 计算课程平均-最高-最低-成绩");
System.out.println("5. 查询学生成绩");
System.out.println("6. 对成绩进行排序并打印所有成绩");
System.out.println("0. 退出系统");
System.out.println("---------------------------------------");
System.out.print("请输入操作序号：");
}
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
StudentScoreManager manager = new StudentScoreManager();
while (true) {
printmenu();
int opeartion = scanner.nextInt();
if (opeartion < 0 || opeartion > 6) {
System.out.println("没有这个选项，请重新选择！");
continue;
}
scanner.nextLine();
switch (opeartion) {
case 1: {
System.out.println("您正在使用功能一：添加学生成绩");
System.out.println("---------------------------------------");
System.out.println("请输入学生学号：");
String id = scanner.nextLine();
System.out.println("请输入学生姓名：");
String name = scanner.nextLine();
System.out.println("请输入课程名称：");
String courseName = scanner.nextLine();
System.out.println("请输入成绩：");
double grade = scanner.nextDouble();
//新建临时类来存储输入的数据
Student student = new Student(id, name);
Course course = new Course(courseName);
Score score = new Score(manager.getScoresLength() + 1, student, course, grade);
//将这个临时的数据塞入,manager这个类的scores-list中,
if (manager.addScore(score)) {
System.out.println("添加成绩数据成功！");
} else {
System.out.println("添加成绩数据失败！");
}
// 等待用户按下回车键继续执行
System.out.println("按下回车键继续...");
scanner.nextLine();
break;
}
case 2: {
System.out.println("您正在使用功能二：删除学生成绩");
System.out.println("---------------------------------------");
System.out.println("请输入学生学号：");
String id = scanner.nextLine();
System.out.println("请输入学生姓名：");
String name = scanner.nextLine();
System.out.println("请输入课程名称：");
String courseName = scanner.nextLine();
Student student = new Student(id, name);
Course course = new Course(courseName);
if (manager.removeScore(student, course)) {
System.out.println("删除学生成绩成功！");
} else {
System.out.println("删除学生成绩失败！没有找到此人");
}
// 等待用户按下回车键继续执行
System.out.println("按下回车键继续...");
scanner.nextLine();
break;
}
case 3: {
System.out.println("您正在使用功能三：修改学生成绩");
System.out.println("---------------------------------------");
System.out.println("请输入学生学号：");
String id = scanner.nextLine();
System.out.println("请输入学生姓名：");
String name = scanner.nextLine();
System.out.println("请输入课程名称：");
String courseName = scanner.nextLine();
System.out.println("请输入新的成绩：");
double newGrade = scanner.nextDouble();
Student student = new Student(id, name);
Course course = new Course(courseName);
if (manager.changeScore(student, course, newGrade)) {
System.out.println("修改学生成绩成功！");
} else {
System.out.println("修改学生成绩失败！没有找到此人");
}
break;
}
case 4: {
System.out.println("您正在使用功能四：计算课程平均-最高-最低-成绩");
System.out.println("---------------------------------------");
System.out.println("请输入课程名称：");
String courseName = scanner.nextLine();
Course course = new Course(courseName);
double average = manager.getAverageGrade(course);
double higest = manager.getHighesrGrade(course);
double lowest = manager.getLowestGrade(course);
System.out.println(courseName + "的平均成绩为：" + average);
System.out.println(courseName + "的最高成绩为：" + higest);
System.out.println(courseName + "的最低成绩为：" + lowest);
// 等待用户按下回车键继续执行
System.out.println("按下回车键继续...");
scanner.nextLine();
break;
}
case 5: {
System.out.println("您正在使用功能五：查询学生成绩");
System.out.println("---------------------------------------");
System.out.println("请输入学生学号：");
String id = scanner.nextLine();
System.out.println("请输入学生姓名：");
String name = scanner.nextLine();
Student student = new Student(id, name);
if (manager.printfixScores(student)) {
//判断的同时可以调用
} else {
System.out.println("没有找到此人");
}
// 等待用户按下回车键继续执行
System.out.println("按下回车键继续...");
scanner.nextLine();
break;
}
case 6: {
System.out.println("您正在使用功能六：对成绩进行排序并打印所有成绩");
System.out.println("---------------------------------------");
manager.printScores();
// 等待用户按下回车键继续执行
System.out.println("按下回车键继续...");
scanner.nextLine();
break;
}
}
}
}
}