一，
前言：
oop 09：7-1 统计Java程序中关键词的出现次数：对Java中字符串，元字符，正则表达式的应用。
oop 10：7-1 容器-HashMap-检索：对Java程序中HashMap的特性对输入内容进行检索的应用。
7-2 容器-HashMap-排序：对Java升序中HashMap的无序性的应用将其排序。
7-3 课程成绩统计程序-2：根据上两个题目对之前所写的课程成绩统计程序进行优化。
7-4 动物发声模拟器（多态）：熟悉Java程序在继承多态上的优势。
oop 11：7-1 容器-ArrayList-排序：学习新容器ArrayList并应用其进行排序。
7-2 课程成绩统计程序-3：应用7-1对课程成绩统计程序进行优化。
7-3 jmu-Java-02基本语法-03-身份证排序：学习使用Comparator接口对目标进行排序。
7-4 jmu-Java-04面向对象进阶-03-接口-自定义接口ArrayIntegerStack：加深对该接口的学习以及应用。
7-5 jmu-Java-03面向对象基础-05-覆盖：对PersonOverride类中的一些功能进行复写。
设计与分析：
oop 09：7-1 统计Java程序中关键词的出现次数。
import java.util.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Main {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
Found found = new Found();
while (true) {
String Line = in.nextLine().trim();
if (Line.isEmpty()) {
System.out.println("Wrong Format");
break;
} else if (Line.equals("exit")) {
found.foundKeyWord();
break;
} else {
found.addLine(Line);
}
}
}
}
class Found {
Set<String> keywords = new TreeSet<>(Arrays.asList(
"abstract", "assert", "boolean", "break", "byte", "case", "catch", "char", "class", "const", "continue", "default", "do", "double", "else", "enum", "extends", "final", "finally", "float", "for", "goto", "if", "implements", "import", "instanceof", "int", "interface", "long", "native", "new", "package", "private", "protected", "public", "return", "short", "static", "strictfp", "super", "switch", "synchronized", "this", "throw", "throws", "transient", "try", "void", "volatile", "while"
));
Map<String, Integer> counter = new TreeMap<>();
Pattern stringPattern = Pattern.compile("\"(?:\\\\.|[^\"])*\"");
Pattern commentPattern = Pattern.compile("//.*|/\\*.*?\\*/", Pattern.DOTALL);
Pattern wordPattern = Pattern.compile("\\b(" + String.join("|", keywords) + ")\\b");
public Found() {
}
public void foundKeyWord() {
for (Map.Entry<String, Integer> entry : counter.entrySet()) {
System.out.println(entry.getValue() + "\t" + entry.getKey());
}
}
public void addLine(String Line) {
Matcher matcher = stringPattern.matcher(Line);
StringBuilder stringBuilder = new StringBuilder(Line);
while (matcher.find()) {
stringBuilder.replace(matcher.start(), matcher.end(), "");
}
Line = stringBuilder.toString();
matcher = commentPattern.matcher(Line);
stringBuilder.setLength(0);
int i = 0;
while (matcher.find()) {
stringBuilder.append(Line, i, matcher.start());
i = matcher.end();
}
stringBuilder.append(Line, i, Line.length());
Line = stringBuilder.toString();
matcher = wordPattern.matcher(Line);
while (matcher.find()) {
String word = matcher.group();
counter.put(word, counter.getOrDefault(word, 0) + 1);
}
}
}
oop 10：7-1 容器-HashMap-检索。
import java.util.HashMap;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner input=new Scanner(System.in);
HashMap<String,String > student=new HashMap<>();
while(true){
String Line=input.nextLine();
if(Line.equals("end")){
break;
}
String[] theLine=Line.split(" ");
student.put(theLine[0],theLine[1]+" "+theLine[2]);
}
String studentID=input.nextLine();
String result=student.get(studentID);
if(result==null){
System.out.println("The student "+studentID+" does not exist");
}else{
System.out.println(studentID+" "+result);
}
}
}
7-2 容器-HashMap-排序。
import java.util.*;
import java.util.List;
public class Main {
public static void main(String[] args) {
Scanner input=new Scanner(System.in);
HashMap<String,String > student=new HashMap<>();
while(true){
String Line=input.nextLine();
if(Line.equals("end")){
break;
}
String[] theLine=Line.split(" ");
student.put(theLine[0],theLine[1]+" "+theLine[2]);
}
List<Map.Entry<String,String>> list=new ArrayList<Map.Entry<String, String>>(student.entrySet());
Collections.sort(list, new Comparator<Map.Entry<String, String>>() {
public int compare(Map.Entry<String, String> o1, Map.Entry<String, String> o2) {
return o2.getKey().compareTo(o1.getKey());
}
});
for (Map.Entry<String, String> student1:list) {
System.out.println(student1.getKey()+" "+student1.getValue());
}
}
}
7-3 课程成绩统计程序-2。
import java.util.Scanner;
// 按两次 Shift 打开“随处搜索”对话框并输入 `show whitespaces`，
// 然后按 Enter 键。现在，您可以在代码中看到空格字符。
public class Main {
public static void main(String[] args) {
String input;
Scanner in = new Scanner(System.in);
Course[] courses = null;
String student_num;
Class[] theClass = null;
// 添加课程 课程名称、课程性质、考核方式
while (true) {
input = in.nextLine();
if (input.equals("end")) {
break;
}
if (checkCourse(input)) {
String[] course = input.split(" ");
if (courses == null) {
courses = new Course[1]; //如果数组为空，先初始化一个长度为1的数组
courses[0] = new Course(course[0], course[1], course[2]); //在数组的第一个位置上添加新的Course对象
} else {
Course[] temp = new Course[courses.length + 1]; //先创建一个长度比原数组大1的临时数组
System.arraycopy(courses, 0, temp, 0, courses.length); //将原数组中的元素复制到临时数组中
temp[temp.length - 1] = new Course(course[0], course[1], course[2]); //在临时数组的最后一个位置上添加新的Course对象
courses = temp; //将临时数组赋值给原数组
}
} else if (checkScore1(input)) {
String[] scores = input.split(" ");
int class_num = Integer.parseInt(scores[0].substring(0, 6));
Student student = new Student(scores[1], scores[0]);
if (theClass == null) {
theClass=new Class[class_num+1];
theClass[class_num] = new Class(class_num, student);
} else if (!checkClass(theClass, class_num)) {
theClass[class_num] = new Class(class_num, student);
} else {
theClass[class_num] = new Class(student);
}
for (int i = 0; i < courses.length; i++) {
if (courses[i].getCourse().equals(scores[2])) {
if (courses[i].getExamKind().equals("考察")) {
InvestigateScore score = new InvestigateScore(Integer.parseInt(scores[3]));
CourseSelection courseSelection = new CourseSelection(courses[i], student, score);
student.setCourseSelection(courseSelection);
} else {
ExamScore score = new ExamScore(Integer.parseInt(scores[3]), Integer.parseInt(scores[4]));
CourseSelection courseSelection = new CourseSelection(courses[i], student, score);
student.setCourseSelection(courseSelection);
}
}
}
} else if (checkScore2(input)) {
String[] scores = input.split(" ");
int class_num = Integer.parseInt(scores[0].substring(0, 6));
Student student = new Student(scores[1], scores[0]);
if (theClass == null) {
theClass=new Class[class_num+1];
theClass[class_num] = new Class(class_num, student);
} else if (!checkClass(theClass, class_num)) {
theClass[class_num] = new Class(class_num, student);
} else {
theClass[class_num] = new Class(student);
}
for (int i = 0; i < courses.length; i++) {
if (courses[i].getCourse().equals(scores[2])) {
ExamScore score = new ExamScore(Integer.parseInt(scores[3]), Integer.parseInt(scores[4]));
CourseSelection courseSelection = new CourseSelection(courses[i], student, score);
student.setCourseSelection(courseSelection);
}
}
} else{
System.out.println("wrong format");
}
}
if(!(theClass ==null)){
outputFirst(theClass);
outputSecond(courses,theClass);
outputThird(theClass);
}else
outputSecond(courses,theClass);
// 输入学生成绩 学号、姓名、课程名称、平时成绩（可选）、期末成绩
// 输出包含三个部分，包括学生所有课程总成绩的平均分、单门课程成绩平均分、单门课程总成绩平均分、班级所有课程总成绩平均分
// 学生所有课程总成绩的平均分(总成绩/课程数）
// 单门课程成绩平均分
// 单门课程总成绩平均分
// 班级所有课程总成绩平均分
}
public static boolean checkScore1(String input) {
return input.matches("\\S+\\s\\S+\\s\\S+\\s\\S+\\s\\S+");
}
public static boolean checkScore2(String input){
return input.matches("\\S+\\s\\S+\\s\\S+\\s\\S+");
}
public static boolean checkCourse(String input) {
return input.matches("\\S+\\s\\S+\\s\\S+");
}
// 判断班级是否存在
public static boolean checkClass(Class[] theClass, int class_num) {
boolean result = false;
for (int i = 0; i < theClass.length; i++) {
if (theClass[i].class_num == class_num) {
result = true;
break;
}
}
return result;
}
// 1）学生课程总成绩平均分按学号由低到高排序输出
// 格式：学号+英文空格+姓名+英文空格+总成绩平均分
// 如果某个学生没有任何成绩信息，输出：学号+英文空格+姓名+英文空格+"did not take any exams"
public static void outputFirst(Class[] theClass){
for(int i=0;i<theClass.length;i++){
for(int j=0;j<theClass[i].students.length;j++){
if(theClass[i].students[j].courseSelection.scores==null){
System.out.println(theClass[i].students[j].student_num+" "+theClass[i].students[j].studentName+"did not take any exams");
}else{
double result=theClass[i].students[j].courseSelection.studentAllCourseScore()/theClass[i].students[j].courseSelection.courses.length;
System.out.println(theClass[i].students[j].student_num+" "+theClass[i].students[j].studentName+" "+result);
}
}
}
}
// 2）单门课程成绩平均分分为三个分值：平时成绩平均分（可选）、期末考试平均分、总成绩平均分，按课程名称的字符顺序输出
// 格式：课程名称+英文空格+平时成绩平均分+英文空格+期末考试平均分+英文空格+总成绩平均分
// 如果某门课程没有任何成绩信息，输出：课程名称+英文空格+"has no grades yet"
public static void outputSecond(Course[] courses,Class[] theClass){
double usualresult=0;
double examresult=0;
double finalresult=0;
if(!(theClass ==null)){
for(int k=0;k<courses.length;k++){
for(int i=0;i< theClass.length;i++){
for(int j=0;j<theClass[i].students.length;j++){
for(int w=0;w<theClass[i].students[j].courseSelection.courses.length;w++){
if(courses[k]!=null&&!theClass[i].students[j].courseSelection.courses[w].getCourse().equals(courses[k].getCourse())){
System.out.println(courses[k].getCourse()+" "+"has no grades yet");
}else{
usualresult+=theClass[i].students[j].courseSelection.scores[w].usualscore;
examresult+=theClass[i].students[j].courseSelection.scores[w].getExamScore();
finalresult=theClass[i].students[j].courseSelection.scores[w].finalScore();
}
}
}
System.out.println(courses[k].getCourse()+" "+usualresult/theClass[i].students.length+" "+examresult/theClass[i].students.length+" "+finalresult/theClass[i].students.length);
}
}
}else{
for(int i=0;i<courses.length;i++){
System.out.println(courses[i].getCourse()+" "+"has no grades yet");
}
}
}
// 3）班级所有课程总成绩平均分按班级由低到高排序输出 格式：班级号+英文空格+总成绩平均分
// 如果某个班级没有任何成绩信息，输出：班级名称+英文空格+ "has no grades yet"
public static void outputThird(Class[] theClass){
for(int i=0;i<theClass.length;i++){
boolean flag=true;
double result=0;
for(int j=0;j<theClass[i].students.length;j++){
if(theClass[i].students[j].courseSelection.scores==null){
flag=false;
}else{
flag=true;
}
result+=theClass[i].students[j].courseSelection.studentAllCourseScore();
}
if(flag){
System.out.println(theClass[i].class_num+" "+result / theClass[i].students.length);
}else{
System.out.println(theClass[i].class_num+" "+"has no grades yet");
}
}
}
}
//选课
class CourseSelection{
public Course[] courses;
public Student student;
public Score[] scores;
public CourseSelection(){
}
public CourseSelection( Course course,Student student,Score score){
if (courses == null && scores== null) {
courses = new Course[1];
courses[0] = course;
scores=new Score[1];
scores[0]=score;
} else {
int currentLength = courses == null ? 0 : courses.length;
Course[] newCourses = new Course[currentLength + 1];
if (courses != null) {
System.arraycopy(courses, 0, newCourses, 0, currentLength);
}
newCourses[currentLength] = course;
courses = newCourses;
this.scores[courses.length-1]=score;
}
this.student=student;
}
public double studentAllCourseScore(){
double result = 0;
for(int i=0;i<courses.length;i++){
result+=scores[i].finalScore();
}
return result;
}
}
class Student{
public String studentName;
public String student_num;
public CourseSelection courseSelection;
public Student(){
}
public Student(String studentName,String student_num){
this.studentName=studentName;
this.student_num=student_num;
}
public void setCourseSelection(CourseSelection courseSelection) {
this.courseSelection = courseSelection;
}
}
class Class{
public int class_num;
public Student[] students;
public Class(){
}
public Class(int class_num,Student student){
this.class_num=class_num;
if (students == null) {
students = new Student[1];
students[0] = student;
} else {
int currentLength = students.length;
Student[] newStudents = new Student[currentLength + 1];
System.arraycopy(students, 0, newStudents, 0, currentLength);
newStudents[currentLength] = student;
students = newStudents;
}
}
public Class(Student student){
if (students == null) {
students = new Student[1];
students[0] = student;
} else {
int currentLength = students.length;
Student[] newStudents = new Student[currentLength + 1];
System.arraycopy(students, 0, newStudents, 0, currentLength);
newStudents[currentLength] = student;
students = newStudents;
}
}
}
class Course{
// 课程名称
private String course;
// 课程性质（选修|必修）
private String character;
// 考核方式
private String examKind;
public Course(){
}
public Course(String course,String character,String examKind){
this.course=course;
this.character=character;
this.examKind=examKind;
}
public String getCourse() {
return course;
}
public void setCourse(String course) {
this.course = course;
}
public String getExamKind() {
return examKind;
}
public void setExamKind(String examKind) {
this.examKind = examKind;
}
}
abstract class Score{
private String scorekind;
public int usualscore=0;
public Score(){
}
public abstract double finalScore();
public abstract int getExamScore();
}
class InvestigateScore extends Score{
private int score;
public InvestigateScore(){
}
public InvestigateScore(int score){
this.score=score;
}
public void setScore(int score) {
this.score = score;
}
public int getScore() {
return score;
}
public double finalScore(){
return this.score;
}
@Override
public int getExamScore() {
return this.score;
}
}
class ExamScore extends Score{
private int score;
public ExamScore(){
}
public ExamScore(int usualscore,int score){
this.score=score;
this.usualscore=usualscore;
}
public int getScore() {
return score;
}
public void setScore(int score) {
this.score = score;
}
public double finalScore(){
return this.usualscore*0.3+this.score*0.7;
}
@Override
public int getExamScore() {
return this.score;
}
}
7-4 动物发声模拟器（多态）。
//动物发生模拟器. 请在下面的【】处添加代码。
public class Main{
public static void main(String[] args) {
Cat cat = new Cat();
Dog dog = new Dog();
Goat goat = new Goat();
speak(cat);
speak(dog);
speak(goat);
}
//定义静态方法speak()
public static void speak(Animal animal){
System.out.println(animal.getAniamlClass()+"："+animal.shout());
}
}
//定义抽象类Animal
abstract class Animal{
public abstract String getAniamlClass();
public abstract String shout();
}
//基于Animal类，定义猫类Cat，并重写两个抽象方法
class Cat extends Animal{
@Override
public String getAniamlClass() {
String theClass = "猫的叫声";
return theClass;
}
@Override
public String shout() {
String shout = "喵喵";
return shout;
}
}
//基于Animal类，定义狗类Dog，并重写两个抽象方法
class Dog extends Animal{
@Override
public String getAniamlClass() {
String theClass = "狗的叫声";
return theClass;
}
@Override
public String shout() {
String shout="汪汪";
return shout;
}
}
//基于Animal类，定义山羊类Goat，并重写两个抽象方法
class Goat extends Animal{
@Override
public String getAniamlClass() {
String theClass = "山羊的叫声";
return theClass;
}
@Override
public String shout() {
String shout="咩咩";
return shout;
}
}
oop 11：7-1 容器-ArrayList-排序。
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
ArrayList<Student> students = new ArrayList<Student>();
Scanner scanner = new Scanner(System.in);
String line = scanner.nextLine();
while (!line.equals("end")) {
String[] parts = line.split(" ");
String id = parts[0];
String name = parts[1];
int mathScore = Integer.parseInt(parts[2]);
int physicsScore = Integer.parseInt(parts[3]);
Student student = new Student(id, name, mathScore, physicsScore);
students.add(student);
line = scanner.nextLine();
}
Collections.sort(students, new Comparator<Student>() {
@Override
public int compare(Student s1, Student s2) {
int sum1 = s1.getMathScore() + s1.getPhysicsScore();
int sum2 = s2.getMathScore() + s2.getPhysicsScore();
if (sum1 != sum2) {
return sum2 - sum1;
} else {
return students.indexOf(s1) - students.indexOf(s2);
}
}
});
for (Student student : students) {
System.out.println(student.getId() + " " + student.getName() + " " + (student.getMathScore() + student.getPhysicsScore()));
}
}
}
class Student {
private String id;
private String name;
private int mathScore;
private int physicsScore;
public Student(String id, String name, int mathScore, int physicsScore) {
this.id = id;
this.name = name;
this.mathScore = mathScore;
this.physicsScore = physicsScore;
}
public String getId() {
return id;
}
public String getName() {
return name;
}
public int getMathScore() {
return mathScore;
}
public int getPhysicsScore() {
return physicsScore;
}
}
7-2 课程成绩统计程序-3。
import java.util.Scanner;
// 按两次 Shift 打开“随处搜索”对话框并输入 `show whitespaces`，
// 然后按 Enter 键。现在，您可以在代码中看到空格字符。
public class Main {
public static void main(String[] args) {
String input;
Scanner in = new Scanner(System.in);
Course[] courses = null;
String student_num;
Class[] theClass = null;
// 添加课程 课程名称、课程性质、考核方式
while (true) {
input = in.nextLine();
if (input.equals("end")) {
break;
}
if (checkCourse(input)) {
String[] course = input.split(" ");
if (courses == null) {
courses = new Course[1]; //如果数组为空，先初始化一个长度为1的数组
courses[0] = new Course(course[0], course[1], course[2]); //在数组的第一个位置上添加新的Course对象
} else {
Course[] temp = new Course[courses.length + 1]; //先创建一个长度比原数组大1的临时数组
System.arraycopy(courses, 0, temp, 0, courses.length); //将原数组中的元素复制到临时数组中
temp[temp.length - 1] = new Course(course[0], course[1], course[2]); //在临时数组的最后一个位置上添加新的Course对象
courses = temp; //将临时数组赋值给原数组
}
} else if (checkScore1(input)) {
String[] scores = input.split(" ");
int class_num = Integer.parseInt(scores[0].substring(0, 6));
Student student = new Student(scores[1], scores[0]);
if (theClass == null) {
theClass=new Class[class_num+1];
theClass[class_num] = new Class(class_num, student);
} else if (!checkClass(theClass, class_num)) {
theClass[class_num] = new Class(class_num, student);
} else {
theClass[class_num] = new Class(student);
}
for (int i = 0; i < courses.length; i++) {
if (courses[i].getCourse().equals(scores[2])) {
if (courses[i].getExamKind().equals("考察")) {
InvestigateScore score = new InvestigateScore(Integer.parseInt(scores[3]));
CourseSelection courseSelection = new CourseSelection(courses[i], student, score);
student.setCourseSelection(courseSelection);
} else {
ExamScore score = new ExamScore(Integer.parseInt(scores[3]), Integer.parseInt(scores[4]));
CourseSelection courseSelection = new CourseSelection(courses[i], student, score);
student.setCourseSelection(courseSelection);
}
}
}
} else if (checkScore2(input)) {
String[] scores = input.split(" ");
int class_num = Integer.parseInt(scores[0].substring(0, 6));
Student student = new Student(scores[1], scores[0]);
if (theClass == null) {
theClass=new Class[class_num+1];
theClass[class_num] = new Class(class_num, student);
} else if (!checkClass(theClass, class_num)) {
theClass[class_num] = new Class(class_num, student);
} else {
theClass[class_num] = new Class(student);
}
for (int i = 0; i < courses.length; i++) {
if (courses[i].getCourse().equals(scores[2])) {
ExamScore score = new ExamScore(Integer.parseInt(scores[3]), Integer.parseInt(scores[4]));
CourseSelection courseSelection = new CourseSelection(courses[i], student, score);
student.setCourseSelection(courseSelection);
}
}
} else{
System.out.println("wrong format");
}
}
if(!(theClass ==null)){
outputFirst(theClass);
outputSecond(courses,theClass);
outputThird(theClass);
}else
outputSecond(courses,theClass);
// 输入学生成绩 学号、姓名、课程名称、平时成绩（可选）、期末成绩
// 输出包含三个部分，包括学生所有课程总成绩的平均分、单门课程成绩平均分、单门课程总成绩平均分、班级所有课程总成绩平均分
// 学生所有课程总成绩的平均分(总成绩/课程数）
// 单门课程成绩平均分
// 单门课程总成绩平均分
// 班级所有课程总成绩平均分
}
public static boolean checkScore1(String input) {
return input.matches("\\S+\\s\\S+\\s\\S+\\s\\S+\\s\\S+");
}
public static boolean checkScore2(String input){
return input.matches("\\S+\\s\\S+\\s\\S+\\s\\S+");
}
public static boolean checkCourse(String input) {
return input.matches("\\S+\\s\\S+\\s\\S+");
}
// 判断班级是否存在
public static boolean checkClass(Class[] theClass, int class_num) {
boolean result = false;
for (int i = 0; i < theClass.length; i++) {
if (theClass[i].class_num == class_num) {
result = true;
break;
}
}
return result;
}
// 1）学生课程总成绩平均分按学号由低到高排序输出
// 格式：学号+英文空格+姓名+英文空格+总成绩平均分
// 如果某个学生没有任何成绩信息，输出：学号+英文空格+姓名+英文空格+"did not take any exams"
public static void outputFirst(Class[] theClass){
for(int i=0;i<theClass.length;i++){
for(int j=0;j<theClass[i].students.length;j++){
if(theClass[i].students[j].courseSelection.scores==null){
System.out.println(theClass[i].students[j].student_num+" "+theClass[i].students[j].studentName+"did not take any exams");
}else{
double result=theClass[i].students[j].courseSelection.studentAllCourseScore()/theClass[i].students[j].courseSelection.courses.length;
System.out.println(theClass[i].students[j].student_num+" "+theClass[i].students[j].studentName+" "+result);
}
}
}
}
// 2）单门课程成绩平均分分为三个分值：平时成绩平均分（可选）、期末考试平均分、总成绩平均分，按课程名称的字符顺序输出
// 格式：课程名称+英文空格+平时成绩平均分+英文空格+期末考试平均分+英文空格+总成绩平均分
// 如果某门课程没有任何成绩信息，输出：课程名称+英文空格+"has no grades yet"
public static void outputSecond(Course[] courses,Class[] theClass){
double usualresult=0;
double examresult=0;
double finalresult=0;
if(!(theClass ==null)){
for(int k=0;k<courses.length;k++){
for(int i=0;i< theClass.length;i++){
for(int j=0;j<theClass[i].students.length;j++){
for(int w=0;w<theClass[i].students[j].courseSelection.courses.length;w++){
if(courses[k]!=null&&!theClass[i].students[j].courseSelection.courses[w].getCourse().equals(courses[k].getCourse())){
System.out.println(courses[k].getCourse()+" "+"has no grades yet");
}else{
usualresult+=theClass[i].students[j].courseSelection.scores[w].usualscore;
examresult+=theClass[i].students[j].courseSelection.scores[w].getExamScore();
finalresult=theClass[i].students[j].courseSelection.scores[w].finalScore();
}
}
}
System.out.println(courses[k].getCourse()+" "+usualresult/theClass[i].students.length+" "+examresult/theClass[i].students.length+" "+finalresult/theClass[i].students.length);
}
}
}else{
for(int i=0;i<courses.length;i++){
System.out.println(courses[i].getCourse()+" "+"has no grades yet");
}
}
}
// 3）班级所有课程总成绩平均分按班级由低到高排序输出 格式：班级号+英文空格+总成绩平均分
// 如果某个班级没有任何成绩信息，输出：班级名称+英文空格+ "has no grades yet"
public static void outputThird(Class[] theClass){
for(int i=0;i<theClass.length;i++){
boolean flag=true;
double result=0;
for(int j=0;j<theClass[i].students.length;j++){
if(theClass[i].students[j].courseSelection.scores==null){
flag=false;
}else{
flag=true;
}
result+=theClass[i].students[j].courseSelection.studentAllCourseScore();
}
if(flag){
System.out.println(theClass[i].class_num+" "+result / theClass[i].students.length);
}else{
System.out.println(theClass[i].class_num+" "+"has no grades yet");
}
}
}
}
//选课
class CourseSelection{
public Course[] courses;
public Student student;
public Score[] scores;
public CourseSelection(){
}
public CourseSelection( Course course,Student student,Score score){
if (courses == null && scores== null) {
courses = new Course[1];
courses[0] = course;
scores=new Score[1];
scores[0]=score;
} else {
int currentLength = courses == null ? 0 : courses.length;
Course[] newCourses = new Course[currentLength + 1];
if (courses != null) {
System.arraycopy(courses, 0, newCourses, 0, currentLength);
}
newCourses[currentLength] = course;
courses = newCourses;
this.scores[courses.length-1]=score;
}
this.student=student;
}
public double studentAllCourseScore(){
double result = 0;
for(int i=0;i<courses.length;i++){
result+=scores[i].finalScore();
}
return result;
}
}
class Student{
public String studentName;
public String student_num;
public CourseSelection courseSelection;
public Student(){
}
public Student(String studentName,String student_num){
this.studentName=studentName;
this.student_num=student_num;
}
public void setCourseSelection(CourseSelection courseSelection) {
this.courseSelection = courseSelection;
}
}
class Class{
public int class_num;
public Student[] students;
public Class(){
}
public Class(int class_num,Student student){
this.class_num=class_num;
if (students == null) {
students = new Student[1];
students[0] = student;
} else {
int currentLength = students.length;
Student[] newStudents = new Student[currentLength + 1];
System.arraycopy(students, 0, newStudents, 0, currentLength);
newStudents[currentLength] = student;
students = newStudents;
}
}
public Class(Student student){
if (students == null) {
students = new Student[1];
students[0] = student;
} else {
int currentLength = students.length;
Student[] newStudents = new Student[currentLength + 1];
System.arraycopy(students, 0, newStudents, 0, currentLength);
newStudents[currentLength] = student;
students = newStudents;
}
}
}
class Course{
// 课程名称
private String course;
// 课程性质（选修|必修）
private String character;
// 考核方式
private String examKind;
public Course(){
}
public Course(String course,String character,String examKind){
this.course=course;
this.character=character;
this.examKind=examKind;
}
public String getCourse() {
return course;
}
public void setCourse(String course) {
this.course = course;
}
public String getExamKind() {
return examKind;
}
public void setExamKind(String examKind) {
this.examKind = examKind;
}
}
abstract class Score{
private String scorekind;
public int usualscore=0;
public Score(){
}
public abstract double finalScore();
public abstract int getExamScore();
}
class InvestigateScore extends Score{
private int score;
public InvestigateScore(){
}
public InvestigateScore(int score){
this.score=score;
}
public void setScore(int score) {
this.score = score;
}
public int getScore() {
return score;
}
public double finalScore(){
return this.score;
}
@Override
public int getExamScore() {
return this.score;
}
}
class ExamScore extends Score{
private int score;
public ExamScore(){
}
public ExamScore(int usualscore,int score){
this.score=score;
this.usualscore=usualscore;
}
public int getScore() {
return score;
}
public void setScore(int score) {
this.score = score;
}
public double finalScore(){
return this.usualscore*0.3+this.score*0.7;
}
@Override
public int getExamScore() {
return this.score;
}
}
7-3 jmu-Java-02基本语法-03-身份证排序。
import java.util.*;
public class Main{
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
int num = in.nextInt();
in.nextLine();
String[] allLine = new String[num];
for(int i = 0; i < num; i++) {
allLine[i] = in.nextLine();
}
Check check = new Check(allLine);
String line = "";
while(true){
line = in.nextLine();
if(line.equals("sort1")){
check.checkFunction1();
}else if(line.equals("sort2")){
check.checkFunction2();
}else{
System.out.println("exit");
break;
}
}
}
}
class Check{
private ArrayList<String> allId = new ArrayList<>();
public Check(String[] line){
for (String theLine:line) {
allId.add(theLine);
}
}
public void checkFunction1(){
ArrayList<String> resultList = new ArrayList<>();
for(String line : this.allId){
String date = line.substring(6, 14);
String formattedDate = date.substring(0, 4) + "-" + date.substring(4, 6) + "-" + date.substring(6);
resultList.add(formattedDate);
}
Collections.sort(resultList);
for(String date : resultList){
System.out.println(date);
}
}
public void checkFunction2(){
Comparator<String> idCardComparator = new Comparator<String>() {
@Override
public int compare(String o1, String o2) {
// 按照年月日升序排序
String date1 = o1.substring(6, 14);
String date2 = o2.substring(6, 14);
return date1.compareTo(date2);
}
};
Collections.sort(allId, idCardComparator);
for(String line : this.allId){
System.out.println(line);
}
}
}
7-4 jmu-Java-04面向对象进阶-03-接口-自定义接口ArrayIntegerStack。
import java.util.Scanner;
import java.util.Arrays;
public class Main {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int n = scanner.nextInt();
ArrayIntegerStack stack = new ArrayIntegerStack(n);
ArrayIntegerStack stack1 = new ArrayIntegerStack(n);
int num=scanner.nextInt();
for (int i = 0; i < num; i++) {
int value = scanner.nextInt();
int result = stack.push(value);
stack1.push(value);
if(result==-1){
System.out.println("error");
}else{
System.out.println(result);
}
}
System.out.println(stack.peek()+","+stack.isEmpty()+","+ stack.size());
System.out.println(Arrays.toString(stack.toArray()));
int x = scanner.nextInt();
for (int i = 0; i < x; i++) {
int value = stack.pop();
System.out.println(value);
}
System.out.println(stack.peek()+","+stack.isEmpty()+","+ stack.size());
System.out.println(Arrays.toString(stack1.toArray()));
}
}
class ArrayIntegerStack {
private int[] array;
private int top;
public ArrayIntegerStack(int capacity) {
array = new int[capacity];
top = -1;
}
public int push(int value) {
if (top == array.length - 1) {
return -1;
} else {
array[++top] = value;
return value;
}
}
public int pop() {
if (top == -1) {
return -1;
} else {
return array[top--];
}
}
public int peek() {
if (top == -1) {
return -1;
} else {
return array[top];
}
}
public boolean isEmpty() {
return top == -1;
}
public int size() {
return top + 1;
}
public Integer[] toArray() {
Integer[] result = new Integer[array.length];
Arrays.fill(result, null);
for (int i = 0; i <= top; i++) {
result[i] = array[i];
}
return result;
}
}
7-5 jmu-Java-03面向对象基础-05-覆盖。
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;
class PersonOverride{
private String name;
private int age;
private boolean gender;
public PersonOverride() {
this("default", 1, true);
}
public PersonOverride(String name, int age, boolean gender) {
this.name = name;
this.age = age;
this.gender = gender;
}
@Override
public String toString() {
return name + "-" + age + "-" + gender;
}
@Override
public boolean equals(Object obj) {
if (obj == null || !(obj instanceof PersonOverride)) {
return false;
}
PersonOverride p = (PersonOverride) obj;
return this.name.equals(p.name) && this.age == p.age && this.gender == p.gender;
}
}
public class Main {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int n1 = scanner.nextInt();
ArrayList<PersonOverride> persons1 = new ArrayList<>();
for (int i = 0; i < n1; i++) {
persons1.add(new PersonOverride());
}
int n2 = scanner.nextInt();
ArrayList<PersonOverride> persons2 = new ArrayList<>();
for (int i = 0; i < n2; i++) {
String name = scanner.next();
int age = scanner.nextInt();
boolean gender = scanner.nextBoolean();
PersonOverride p = new PersonOverride(name, age, gender);
if (!persons2.contains(p)) {
persons2.add(p);
}
}
for (PersonOverride p : persons1) {
System.out.println(p);
}
for (PersonOverride p : persons2) {
System.out.println(p);
}
System.out.println(persons2.size());
System.out.println(Arrays.toString(PersonOverride.class.getConstructors()));
}
}
踩坑心得： 对于Comparator接口使用还不熟练底层逻辑还没弄明白。 总结： 面对较难的问题时缺乏解决问题的耐心和毅力。我意识到自己在学习中存在一些不足之处。首先，我发现自己有时候会过于追求完美，导致耗费过多的时间和精力在细节上，而忽略了更重要的事情。其次，我有时候会过于依赖自己的能力，而不愿意向他人寻求帮助或反馈，这可能会影响我的学习效率和质量。 二， 对于边讲边练的教学方式强度较大，迭代的方式对于基础较差的同学容易放弃对于基础较好的同学有利于对知识的理解加深有利有弊。对于教学过程（PTA题目集驱动）我认为应该对测试点给予提示有时候可能一点错可是测试点一点提示没有耗费了很多时间我认为对于Java的学习并无益处，反而浪费时间精力。对于教学模式（BOPPPS)我认为形式很好但是前提是每个人都用心准备，在听的过程中明显个别糊弄了事，学习效果不好，而且对于我们学生来说第一次接触JavaFX对于每个方法在实际应用时应该注意什么一无所知，不像老师有实际经验，难以抓住重点，听的时候也不知道该重点听什么，在准备时发现我们组所讲解的地方跟别的组有重合需要别的组的内容补充，这就导致其他同学在听的时候更加云里雾里，相信别的组也存在这种问题。形式新颖但是效果很差。 标签：11,String,int,09,pta,class,theClass,new,public From： https://www.cnblogs.com/guanguanshuibuzhao/p/17509883.html