一.前言
这一次博客将主要介绍在第7、8次PTA作业和期末考试中涉及到的知识点。
(1)题目集7:
7-1 容器-HashMap-检索
7-2 容器-HashMap-排序
7-3 课程成绩统计程序-2
7-4 动物发声模拟器(多态)
这几道题目中只有课程成绩统计程序-2难度较大,其他的三道题目考察的都是较为基础的内容,代码量也不多。HashMap中检索与排序、多态这三道题通过学习课本上的基础就能够完成。
(2)题目集8:
7-1 容器-ArrayList-排序
7-2 课程成绩统计程序-3
7-3 jmu-Java-02基本语法-03-身份证排序
7-4 jmu-Java-04面向对象进阶-03-接口-自定义接口ArrayIntegerStack
7-5 jmu-Java-03面向对象基础-05-覆盖
这几道题目中7-2 课程成绩统计程序-3难度最大,同时和题目集7中的课程成绩统计程序-2一样,都存在着浮点误差,这一点我没能解决。7-1、7-2、7-4则相对简单,而7-5覆盖因为对该内容不怎么了解,起初不知道如何进行设计,在学习了相关知识后才解决问题,有一定的难度。
(3)期末考试:
期末考试的题目类型和期中考试相同,分为选择题和编程题。编程题具有明显的难度阶梯,由易到难层层递进,同时具备了区分度和适当的难度。
7-1 立体图形问题
7-2 魔方问题
7-3 魔方排序问题
7-4 销售问题(附加题)
二.设计与分析
(1)7-3 课程成绩统计程序-2:
课程成绩统计程序-2在第一次的基础上增加了实验课,以下加粗字体显示为本次新增的内容。
某高校课程从性质上分为:必修课、选修课、实验课,从考核方式上分为:考试、考察、实验。
考试的总成绩由平时成绩、期末成绩分别乘以权重值得出,比如平时成绩权重0.3,期末成绩权重0.7,总成绩=平时成绩*0.3+期末成绩*0.7。
考察的总成绩直接等于期末成绩
实验的总成绩等于课程每次实验成绩的平均分
必修课的考核方式必须为考试,选修课可以选择考试、考察任一考核方式。实验课的成绩必须为实验。
1、输入:
包括课程、课程成绩两类信息。
课程信息包括:课程名称、课程性质、考核方式(可选,如果性质是必修课,考核方式可以没有)三个数据项。
课程信息格式:课程名称+英文空格+课程性质+英文空格+考核方式
课程性质输入项:必修、选修、实验
考核方式输入选项:考试、考察、实验
考试/考查课程成绩信息包括:学号、姓名、课程名称、平时成绩(可选)、期末成绩
考试/考查课程信息格式:学号+英文空格+姓名+英文空格+课程名称+英文空格+平时成绩+英文空格+期末成绩
实验课程成绩信息包括:学号、姓名、课程名称、实验次数、每次成绩
实验次数至少4次,不超过9次
实验课程信息格式:学号+英文空格+姓名+英文空格+课程名称+英文空格+实验次数+英文空格+第一次实验成绩+...+英文空格+最后一次实验成绩
以上信息的相关约束:
1)平时成绩和期末成绩的权重默认为0.3、0.7
2)成绩是整数,不包含小数部分,成绩的取值范围是【0,100】
3)学号由8位数字组成
4)姓名不超过10个字符
5)课程名称不超过10个字符
6)不特别输入班级信息,班级号是学号的前6位。
2、输出:
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。
为避免误差,平均分的计算方法为累加所有符合条件的单个成绩,最后除以总数。
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"
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
考试/考察课程成绩格式: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
实验课成绩格式:课程名称+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"
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"
异常情况:
1)如果解析某个成绩信息时,课程名称不在已输入的课程列表中,输出:学号+英文空格+姓名+英文空格+":"+课程名称+英文空格+"does not exist"
2)如果解析某个成绩信息时,输入的成绩数量和课程的考核方式不匹配,输出:学号+英文空格+姓名+英文空格+": access mode mismatch"
以上两种情况如果同时出现,按第一种情况输出结果。
3)如果解析某个课程信息时,输入的课程性质和课程的考核方式不匹配,输出:课程名称+" : course type & access mode mismatch"
4)格式错误以及其他信息异常如成绩超出范围等,均按格式错误处理,输出"wrong format"
5)若出现重复的课程/成绩信息,只保留第一个课程信息,忽略后面输入的。
信息约束:
1)成绩平均分只取整数部分,小数部分丢弃
参考类图(与第一次相同,其余内容自行补充):
输入样例1:
在这里给出一组输入。例如:
java 实验 实验
20201103 张三 java 4 70 80 90
end
输出样例1:
在这里给出相应的输出。例如:
20201103 张三 : access mode mismatch
20201103 张三 did not take any exams
java has no grades yet
202011 has no grades yet
输入样例2:
在这里给出一组输入。例如:
java 实验 实验
20201103 张三 java 3 70 80 90
end
输出样例2:
在这里给出相应的输出。例如:
wrong format
java has no grades yet
输入样例3:
在这里给出一组输入。例如:
java 必修 实验
20201103 张三 java 3 70 80 90 100
end
输出样例3:
在这里给出相应的输出。例如:
java : course type & access mode mismatch
wrong format
输入样例4:
在这里给出一组输入。例如:
java 必修 实验
20201103 张三 java 4 70 80 90 105
end
输出样例4:
在这里给出相应的输出。例如:
java : course type & access mode mismatch
wrong format
输入样例5:
在这里给出一组输入。例如:
java 选修 考察
C语言 选修 考察
java实验 实验 实验
编译原理 必修 考试
20201101 王五 C语言 76
20201216 李四 C语言 78
20201307 张少军 编译原理 82 84
20201103 张三 java实验 4 70 80 90 100
20201118 郑觉先 java 80
20201328 刘和宇 java 77
20201220 朱重九 java实验 4 60 60 80 80
20201132 王萍 C语言 40
20201302 李梦涵 C语言 68
20201325 崔瑾 编译原理 80 84
20201213 黄红 java 82
20201209 赵仙芝 java 76
end
输出样例5:
在这里给出相应的输出。例如:
20201101 王五 76
20201103 张三 85
20201118 郑觉先 80
20201132 王萍 40
20201209 赵仙芝 76
20201213 黄红 82
20201216 李四 78
20201220 朱重九 70
20201302 李梦涵 68
20201307 张少军 83
20201325 崔瑾 82
20201328 刘和宇 77
C语言 65 65
java 78 78
java实验 77
编译原理 81 84 82
202011 70
202012 76
202013 77
题目给出的类图具有很好的指引作用,根据实例类图建立相关类可以完成代码的基础部分。在成绩计算相关的算法则需要付出一定的时间精力思考。
源代码:
import java.util.*; import java.text.Collator; public class Main { public static void main(String[] args) { ArrayList<Class> classes = new ArrayList<>(); ArrayList<Course> courses = new ArrayList<>(); ArrayList<Student> students = new ArrayList<>(); ArrayList<CourseSelection> courseSelections = new ArrayList<>(); Scanner input = new Scanner(System.in); while (true) { String strring = input.nextLine(); if (strring.equals("end")) { break; } String[] nextLine = strring.split(" "); if (nextLine.length == 3) { addCourse(nextLine,courses); } else if (nextLine.length == 5) { addScoredCourseSelection1(nextLine,courseSelections,students,courses); } else if (nextLine.length == 4) { addScoredCourseSelection2(nextLine, courses, students, courseSelections); } else if (nextLine.length > 5) { addScoredCourseSelection3(nextLine,courses,students,courseSelections); } else { System.out.println("wrong format"); } } for (Student student:students ) { int classNumber = Integer.parseInt(student.getStudentNumber()) / 100; if (classes.isEmpty()) { Class clas = new Class(); clas.setClassNumber(classNumber); clas.getStudents().add(student); classes.add(clas); } else { ListIterator<Class> iterator = classes.listIterator(); while (iterator.hasNext()) { Class clas = iterator.next(); if (clas.getClassNumber() == classNumber) { clas.getStudents().add(student); break; } else { if (classes.indexOf(clas) == classes.size() - 1) { Class clasNew = new Class(); clasNew.setClassNumber(classNumber); clasNew.getStudents().add(student); iterator.add(clasNew); } } } } } Collections.sort(classes, Comparator.comparingInt(o -> o.getClassNumber())); for (Class clas:classes ) { clas.setClassAverageScore(print1(clas.getStudents(), courseSelections)); } print2(courses, courseSelections); for (Class clas:classes ) { if (clas.getClassAverageScore() == -1) { System.out.println(clas.getClassNumber() + " has no grades yet"); } else System.out.println(clas.getClassNumber() + " " + clas.getClassAverageScore()); } } public static int print1(ArrayList<Student> students, ArrayList<CourseSelection> courseSelections) { int classAverageScore = 0; Collections.sort(students, Comparator.comparingInt(o -> Integer.parseInt(o.getStudentNumber()))); for (Student student:students ) { int averageScore = 0; int courseNum = 0; for (CourseSelection cs:courseSelections ) { if (cs.getStudent().getStudentNumber().equals(student.getStudentNumber())) { averageScore += cs.getScore().getTotalScore(); courseNum ++; } } if (courseNum == 0) { System.out.println(student.getStudentNumber() + " " + student.getStudentName() + " did not take any exams"); return -1; } else { averageScore /= courseNum; System.out.println(student.getStudentNumber() + " " + student.getStudentName() + " " + averageScore); } classAverageScore += averageScore; } return classAverageScore / students.size(); } public static void print2(ArrayList<Course> courses, ArrayList<CourseSelection> courseSelections) { Collections.sort(courses, (o1, o2) -> { Collator collator = Collator.getInstance(Locale.CHINA); return collator.compare(o1.getCourseName(), o2.getCourseName()); }); for (Course course:courses ) { int courseAverageScore = 0; int courseDailyPerformance = 0; int courseFinalGrade = 0; int studentNum = 0; for (CourseSelection cs:courseSelections ) { if (course.getCourseName().equals(cs.getCourse().getCourseName())) { courseAverageScore += cs.getScore().getTotalScore(); courseDailyPerformance += cs.getScore().getDailyPerformance(); courseFinalGrade += cs.getScore().getFinalGrade(); studentNum ++; } } if (studentNum == 0) { System.out.println(course.getCourseName() + " has no grades yet"); } else { courseAverageScore /= studentNum; courseDailyPerformance /= studentNum; courseFinalGrade /= studentNum; if (course.getAssessmentMethod().equals("考试")) { System.out.println(course.getCourseName() + " " + courseDailyPerformance + " " + courseFinalGrade + " " + courseAverageScore); } else if (course.getAssessmentMethod().equals("考察")) { System.out.println(course.getCourseName() + " " + courseFinalGrade + " " + courseAverageScore); } else { System.out.println(course.getCourseName() + " " + courseAverageScore); } } } } public static boolean isCourseExist(String courseName, ArrayList<Course> courses, int length, Student student) { for (Course course:courses ) { if (course.getCourseName().equals(courseName)) { if ((course.getAssessmentMethod().equals("考试") && length != 5) || (course.getAssessmentMethod().equals("考察") && length != 4) || (course.getAssessmentMethod().equals("实验") && length != 4)) { System.out.println(student.getStudentNumber() + " " + student.getStudentName() + " : access mode mismatch"); return false; } else return true; } } System.out.println(courseName + " does not exist"); return true; } public static boolean RepetitiveCourses(Course course,ArrayList<Course> courses) { for (Course cou:courses ) { if (cou.getCourseName().equals(course.getCourseName())) return true; } return false; } public static boolean RepetitiveScores(CourseSelection courseSelection,ArrayList<CourseSelection> courseSelections) { for (CourseSelection cs:courseSelections ) { if (cs.getStudent().getStudentName().equals(courseSelection.getStudent().getStudentName())) { if (cs.getCourse().getCourseName().equals(courseSelection.getCourse().getCourseName())) { return true; } } } return false; } public static void addCourse(String[] nextLine, ArrayList<Course> courses) { Course course = new Course(nextLine[0], nextLine[1], nextLine[2]); if (RepetitiveCourses(course,courses)) return; if (nextLine[0].length() > 10 || (!nextLine[1].equals("必修") && !nextLine[1].equals("选修") && !nextLine[1].equals("实验")) || (!nextLine[2].equals("考试") && !nextLine[2].equals("考察") && !nextLine[2].equals("实验"))) { System.out.println("wrong format"); return; } if ((course.getCourseNature().equals("必修") && !course.getAssessmentMethod().equals("考试")) || (course.getCourseNature().equals("实验") && !course.getAssessmentMethod().equals("实验"))) { System.out.println(course.getCourseName() + " : course type & access mode mismatch"); return; } courses.add(course); } public static void addScoredCourseSelection1(String[] nextLine, ArrayList<CourseSelection> courseSelections, ArrayList<Student> students, ArrayList<Course> courses) { if (!nextLine[3].matches("100|[1-9][0-9]|[0-9]") || !nextLine[4].matches("100|[1-9][0-9]|[0-9]") || nextLine[0].length() != 8 || nextLine[1].length() > 10) { System.out.println("wrong format"); return; } Student student = new Student(nextLine[0], nextLine[1]); Iterator<Student> iterator = students.iterator(); while (iterator.hasNext()) { Student stu = iterator.next(); if (stu.getStudentNumber().equals(student.getStudentNumber())) { iterator.remove(); } } students.add(student); if (isCourseExist(nextLine[2], courses, nextLine.length, student)) { Score score = new ExaminationResults(Integer.parseInt(nextLine[3]), Integer.parseInt(nextLine[4])); for (Course course:courses ) { if (course.getCourseName().equals(nextLine[2])) { CourseSelection courseSelection = new CourseSelection(course, student, score); if (RepetitiveScores(courseSelection,courseSelections)) continue; courseSelections.add(courseSelection); } } } } public static void addScoredCourseSelection2(String[] nextLine, ArrayList<Course> courses, ArrayList<Student> students, ArrayList<CourseSelection> courseSelections) { if (!nextLine[3].matches("100|[1-9][0-9]|[0-9]") || nextLine[0].length() != 8 || nextLine[1].length() > 10) { System.out.println("wrong format"); return; } Student student = new Student(nextLine[0], nextLine[1]); Iterator<Student> iterator = students.iterator(); while (iterator.hasNext()) { Student stu = iterator.next(); if (stu.getStudentNumber().equals(student.getStudentNumber())) { iterator.remove(); } } students.add(student); if (isCourseExist(nextLine[2], courses, nextLine.length, student)) { Score score = new AssessmentResults(Integer.parseInt(nextLine[3])); for (Course course:courses ) { if (course.getCourseName().equals(nextLine[2])) { CourseSelection courseSelection = new CourseSelection(course, student, score); if (RepetitiveScores(courseSelection,courseSelections)) continue; courseSelections.add(courseSelection); } } } } public static void addScoredCourseSelection3(String[] nextLine, ArrayList<Course> courses, ArrayList<Student> students, ArrayList<CourseSelection> courseSelections) { ArrayList<Integer> results = new ArrayList<>(); if (nextLine[0].length() != 8 || nextLine[1].length() > 10 || !nextLine[3].matches("[4-9]")) { System.out.println("wrong format"); return; } for (int i = 4;i < nextLine.length;i ++) { if (!nextLine[i].matches("100|[1-9][0-9]|[0-9]")) { System.out.println("wrong format"); return; } results.add(Integer.parseInt(nextLine[i])); } Student student = new Student(nextLine[0], nextLine[1]); Iterator<Student> iterator = students.iterator(); while (iterator.hasNext()) { Student stu = iterator.next(); if (stu.getStudentNumber().equals(student.getStudentNumber())) { iterator.remove(); } } students.add(student); if (isCourseExist(nextLine[2], courses, nextLine.length - Integer.parseInt(nextLine[3]), student)) { Score score = new ExperimentalResults(results, Integer.parseInt(nextLine[3])); for (Course course:courses ) { if (course.getCourseName().equals(nextLine[2])) { CourseSelection courseSelection = new CourseSelection(course, student, score); if (RepetitiveScores(courseSelection,courseSelections)) continue; courseSelections.add(courseSelection); } } } } } abstract class Score { private int dailyPerformance; // 平时成绩 private int finalGrade; // 期末成绩 public Score() { } public Score(int finalGrade) { this.finalGrade = finalGrade; } public Score(int dailyPerformance, int finalGrade) { this.dailyPerformance = dailyPerformance; this.finalGrade = finalGrade; } public int getDailyPerformance() { return dailyPerformance; } public void setDailyPerformance(int dailyPerformance) { this.dailyPerformance = dailyPerformance; } public int getFinalGrade() { return finalGrade; } public void setFinalGrade(int finalGrade) { this.finalGrade = finalGrade; } public abstract int getTotalScore(); } class ExaminationResults extends Score { public ExaminationResults(int dailyPerformance, int finalGrade) { super(dailyPerformance, finalGrade); } @Override public int getTotalScore() { return (int) (getDailyPerformance() * 0.3 + getFinalGrade() * 0.7); } } class AssessmentResults extends Score { public AssessmentResults(int finalGrade) { super(finalGrade); } public int getTotalScore() { return getFinalGrade(); } } class ExperimentalResults extends Score { private ArrayList<Integer> results = new ArrayList<>(); private int NumberOfTests; public ExperimentalResults(ArrayList<Integer> results, int numberOfTests) { this.results = results; this.NumberOfTests = numberOfTests; } public ArrayList<Integer> getResults() { return results; } public void setResults(ArrayList<Integer> results) { this.results = results; } public int getNumberOfTests() { return NumberOfTests; } public void setNumberOfTests(int numberOfTests) { NumberOfTests = numberOfTests; } @Override public int getTotalScore() { int totalScore = 0; for (int score:this.results ) { totalScore += score; } return totalScore / this.NumberOfTests; } } class Course { private String courseName; // 课程名称 private String courseNature; // 课程性质 private String AssessmentMethod; // 考核方式 public Course(String courseName, String courseNature, String assessmentMethod) { this.courseName = courseName; this.courseNature = courseNature; AssessmentMethod = assessmentMethod; } public Course() { } public String getCourseName() { return courseName; } public void setCourseName(String courseName) { this.courseName = courseName; } public String getCourseNature() { return courseNature; } public void setCourseNature(String courseNature) { this.courseNature = courseNature; } public String getAssessmentMethod() { return AssessmentMethod; } public void setAssessmentMethod(String assessmentMethod) { AssessmentMethod = assessmentMethod; } } class Student { private String studentNumber; private String studentName; public Student(String studentNumber, String studentName) { this.studentNumber = studentNumber; this.studentName = studentName; } public String getStudentNumber() { return studentNumber; } public void setStudentNumber(String studentNumber) { this.studentNumber = studentNumber; } public String getStudentName() { return studentName; } } class Class { private int classNumber; private int classAverageScore; private ArrayList<Student> students = new ArrayList<>(); public Class(int classNumber, ArrayList<Student> students) { this.classNumber = classNumber; this.students = students; } public Class() { } public int getClassAverageScore() { return classAverageScore; } public void setClassAverageScore(int classAverageScore) { this.classAverageScore = classAverageScore; } public int getClassNumber() { return classNumber; } public void setClassNumber(int classNumber) { this.classNumber = classNumber; } public ArrayList<Student> getStudents() { return students; } public void setStudents(ArrayList<Student> students) { this.students = students; } public void addStudent(Student student) { students.add(student); } } class CourseSelection { private Course course; private Student student; private Score score; public CourseSelection(Course course, Student student, Score score) { this.course = course; this.student = student; this.score = score; } public Course getCourse() { return course; } public void setCourse(Course course) { this.course = course; } public Student getStudent() { return student; } public void setStudent(Student student) { this.student = student; } public Score getScore() { return score; } public void setScore(Score score) { this.score = score; } }
类图设计:
这次的成绩计算题目在第一次的基础上添加了实验课的内容,题目的整体结构基本没变,所以相应的添加了ExperimentalResults类来完成相应的操作。没能完成第14个测试点。浮点误差不知道应该如何解决。
7-2 课程成绩统计程序-3
课程成绩统计程序-3在第二次的基础上修改了计算总成绩的方式,
要求:修改类结构,将成绩类的继承关系改为组合关系,成绩信息由课程成绩类和分项成绩类组成,课程成绩类组合分项成绩类,分项成绩类由成绩分值和权重两个属性构成。
完成课程成绩统计程序-2、3两次程序后,比较继承和组合关系的区别。思考一下哪一种关系运用上更灵活,更能够适应变更。
题目最后的参考类图未做修改,大家根据要求自行调整,以下内容加粗字体显示的内容为本次新增的内容。
某高校课程从性质上分为:必修课、选修课、实验课,从考核方式上分为:考试、考察、实验。
考试的总成绩由平时成绩、期末成绩分别乘以权重值得出,比如平时成绩权重0.3,期末成绩权重0.7,总成绩=平时成绩*0.3+期末成绩*0.7。
考察的总成绩直接等于期末成绩
实验的总成绩等于课程每次实验成绩乘以权重后累加而得。
课程权重值在录入课程信息时输入。(注意:所有分项成绩的权重之和应当等于1)
必修课的考核方式必须为考试,选修课可以选择考试、考察任一考核方式。实验课的成绩必须为实验。
1、输入:
包括课程、课程成绩两类信息。
课程信息包括:课程名称、课程性质、考核方式、分项成绩数量、每个分项成绩的权重。
考试课信息格式:课程名称+英文空格+课程性质+英文空格+考核方式+英文空格+平时成绩的权重+英文空格+期末成绩的权重
考察课信息格式:课程名称+英文空格+课程性质+英文空格+考核方式
实验课程信息格式:课程名称+英文空格+课程性质+英文空格+考核方式+英文空格+分项成绩数量n+英文空格+分项成绩1的权重+英文空格+。。。+英文空格+分项成绩n的权重
实验次数至少4次,不超过9次
课程性质输入项:必修、选修、实验
考核方式输入选项:考试、考察、实验
考试/考查课程成绩信息包括:学号、姓名、课程名称、平时成绩(可选)、期末成绩
考试/考查课程成绩信息格式:学号+英文空格+姓名+英文空格+课程名称+英文空格+平时成绩+英文空格+期末成绩
实验课程成绩信息包括:学号、姓名、课程名称、每次成绩{在系列-2的基础上去掉了(实验次数),实验次数要和实验课程信息中输入的分项成绩数量保持一致}
实验课程信息格式:学号+英文空格+姓名+英文空格+课程名称+英文空格+第一次实验成绩+...+英文空格+最后一次实验成绩
以上信息的相关约束:
1)成绩是整数,不包含小数部分,成绩的取值范围是【0,100】
2)学号由8位数字组成
3)姓名不超过10个字符
4)课程名称不超过10个字符
5)不特别输入班级信息,班级号是学号的前6位。
2、输出:
输出包含三个部分,包括学生所有课程总成绩的平均分、单门课程总成绩平均分、班级所有课程总成绩平均分。
为避免四舍五入误差,
计算单个成绩时,分项成绩乘以权重后要保留小数位,计算总成绩时,累加所有分项成绩的权重分以后,再去掉小数位。
学生总成绩/整个班/课程平均分的计算方法为累加所有符合条件的单个成绩,最后除以总数。
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"
2)单门课程成绩按课程名称的字符顺序输出
课程成绩输出格式:课程名称+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"
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"
异常情况:
1)如果解析某个成绩信息时,课程名称不在已输入的课程列表中,输出:学号+英文空格+姓名+英文空格+":"+课程名称+英文空格+"does not exist"
2)如果解析某个成绩信息时,输入的成绩数量和课程的考核方式不匹配,输出:学号+英文空格+姓名+英文空格+": access mode mismatch"
以上两种情况如果同时出现,按第一种情况输出结果。
3)如果解析某个课程信息时,输入的课程性质和课程的考核方式不匹配,输出:课程名称+" : course type & access mode mismatch"
4)格式错误以及其他信息异常如成绩超出范围等,均按格式错误处理,输出"wrong format"
5)若出现重复的课程/成绩信息,只保留第一个课程信息,忽略后面输入的。
6)如果解析实验课程信息时,输入的分项成绩数量值和分项成绩权重的个数不匹配,输出:课程名称+" : number of scores does not match"
7)如果解析考试课、实验课时,分项成绩权重值的总和不等于1,输出:课程名称+" : weight value error"
信息约束:
1)成绩平均分只取整数部分,小数部分丢弃
参考类图(与第一次相同,其余内容自行补充):
输入样例1:
在这里给出一组输入。例如:
java 实验 实验 4 0.2 0.3 0.2 0.3
end
输出样例1:
在这里给出相应的输出。例如:
java has no grades yet
输入样例2:
在这里给出一组输入。例如:
java 实验 实验 4 0.2 0.3 0.2
end
输出样例2:
在这里给出相应的输出。例如:
java : number of scores does not match
输入样例3:
在这里给出一组输入。例如:
java 实验 实验 4 0.2 0.3 0.2 0.1
end
输出样例3:
在这里给出相应的输出。例如:
java : weight value error
输入样例4:
在这里给出一组输入。例如:
java 实验 实验 4 0.2 0.3 0.2 0.3
20201116 张三 java 70 80 90 100
end
输出样例4:
在这里给出相应的输出。例如:
20201116 张三 86
java 86
202011 86
输入样例5:
在这里给出一组输入。例如:
java 实验 实验 4 0.2 0.3 0.2 0.3
20201116 张三 java 70 80 90 100 80
end
输出样例5:
在这里给出相应的输出。例如:
20201116 张三 : access mode mismatch
20201116 张三 did not take any exams
java has no grades yet
202011 has no grades yet
源代码:
1 import java.util.*; 2 import java.text.Collator; 3 4 public class Main { 5 public static void main(String[] args) { 6 ArrayList<Class> classes = new ArrayList<>(); 7 ArrayList<Course> courses = new ArrayList<>(); 8 ArrayList<Student> students = new ArrayList<>(); 9 ArrayList<CourseSelection> courseSelections = new ArrayList<>(); 10 Scanner input = new Scanner(System.in); 11 while (true) { 12 String strrings = input.nextLine(); 13 if (strrings.equals("end")) { 14 break; 15 } 16 String[] nextLine = strrings.split(" "); 17 if (nextLine[1].equals("必修") || nextLine[1].equals("选修") || nextLine[1].equals("实验")) { 18 addCourse(nextLine,courses); 19 } else if (nextLine.length == 5) { 20 addScoredCourseSelection1(nextLine,courseSelections,students,courses); 21 } else if (nextLine.length == 4) { 22 addScoredCourseSelection2(nextLine, courses, students, courseSelections); 23 } else if (nextLine.length > 5) { 24 addScoredCourseSelection3(nextLine,courses,students,courseSelections); 25 } else { 26 System.out.println("wrong format"); 27 } 28 } 29 for (Student student:students 30 ) { 31 int classNumber = Integer.parseInt(student.getstudentNumberID()) / 100; 32 if (classes.isEmpty()) { 33 Class clasS = new Class(); 34 clasS.setClassNumber(classNumber); 35 clasS.getStudents().add(student); 36 classes.add(clasS); 37 } else { 38 ListIterator<Class> iterator = classes.listIterator(); 39 while (iterator.hasNext()) { 40 Class clas = iterator.next(); 41 if (clas.getClassNumber() == classNumber) { 42 clas.getStudents().add(student); 43 break; 44 } else { 45 if (classes.indexOf(clas) == classes.size() - 1) { 46 Class clasNew = new Class(); 47 clasNew.setClassNumber(classNumber); 48 clasNew.getStudents().add(student); 49 iterator.add(clasNew); 50 } 51 } 52 } 53 } 54 } 55 Collections.sort(classes, Comparator.comparingInt(O -> O.getClassNumber())); 56 for (Class clas:classes 57 ) { 58 clas.setClassAverageScore(print1(clas.getStudents(), courseSelections)); 59 } 60 print2(courses, courseSelections); 61 for (Class clas:classes 62 ) { 63 if (clas.getClassAverageScore() == -1) { 64 System.out.println(clas.getClassNumber() + " has no grades yet"); 65 } else System.out.println(clas.getClassNumber() + " " + clas.getClassAverageScore()); 66 } 67 } 68 public static int print1(ArrayList<Student> students, ArrayList<CourseSelection> courseSelections) { 69 int classAverageScore = 0; 70 Collections.sort(students, Comparator.comparingInt(O -> Integer.parseInt(O.getstudentNumberID()))); 71 for (Student student:students 72 ) { 73 int averageScore = 0; 74 int courseNum = 0; 75 for (CourseSelection cs:courseSelections 76 ) { 77 if (cs.getStudent().getstudentNumberID().equals(student.getstudentNumberID())) { 78 averageScore += cs.getScore().getTotalScore(); 79 courseNum ++; 80 } 81 } 82 if (courseNum == 0) { 83 System.out.println(student.getstudentNumberID() + " " + student.getStudentName() + " did not take any exams"); 84 return -1; 85 } else { 86 averageScore /= courseNum; 87 System.out.println(student.getstudentNumberID() + " " + student.getStudentName() + " " + averageScore); 88 } 89 classAverageScore += averageScore; 90 } 91 return classAverageScore / students.size(); 92 } 93 public static void print2(ArrayList<Course> courses, ArrayList<CourseSelection> courseSelections) { 94 Collections.sort(courses, (O1, O2) -> { 95 Collator collator = Collator.getInstance(Locale.CHINA); 96 return collator.compare(O1.getCourseName(), O2.getCourseName()); 97 }); 98 for (Course course:courses 99 ) { 100 int courseAverageScore = 0; 101 int studentNum = 0; 102 for (CourseSelection cs:courseSelections 103 ) { 104 if (course.getCourseName().equals(cs.getCourse().getCourseName())) { 105 courseAverageScore += cs.getScore().getTotalScore(); 106 studentNum ++; 107 } 108 } 109 if (studentNum == 0) { 110 System.out.println(course.getCourseName() + " has no grades yet"); 111 } else { 112 courseAverageScore /= studentNum; 113 System.out.println(course.getCourseName() + " " + courseAverageScore); 114 } 115 116 } 117 } 118 public static boolean isCourseExist(String courseName, ArrayList<Course> courses, int length, Student student) { 119 for (Course course:courses 120 ) { 121 if (course.getCourseName().equals(courseName)) { 122 if ((course.getAssessmentMethod().equals("考试") && length == 5) || 123 (course.getAssessmentMethod().equals("考察") && length == 4) || 124 (course.getAssessmentMethod().equals("实验") && length == course.getWeightNumber())) { 125 return true; 126 } else { 127 System.out.println(student.getstudentNumberID() + " " + student.getStudentName() + " : access mode mismatch"); 128 return false; 129 } 130 } 131 } 132 System.out.println(courseName + " does not exist"); 133 return false; 134 } 135 public static boolean RepetitiveCourses(String courseName,ArrayList<Course> courses) { 136 for (Course cou:courses 137 ) { 138 if (cou.getCourseName().equals(courseName)) return true; 139 } 140 return false; 141 } 142 public static boolean RepetitiveScores(CourseSelection courseSelection,ArrayList<CourseSelection> courseSelections) { 143 for (CourseSelection cs:courseSelections 144 ) { 145 if (cs.getStudent().getStudentName().equals(courseSelection.getStudent().getStudentName())) { 146 if (cs.getCourse().getCourseName().equals(courseSelection.getCourse().getCourseName())) { 147 return true; 148 } 149 } 150 } 151 return false; 152 } 153 public static void addCourse(String[] nextLine, ArrayList<Course> courses) { 154 if (RepetitiveCourses(nextLine[0],courses)) return; 155 if (nextLine[0].length() > 10 || 156 (!nextLine[2].equals("考试") && !nextLine[2].equals("考察") && !nextLine[2].equals("实验"))) { 157 System.out.println("wrong format"); 158 return; 159 } 160 int weightNumber; 161 double totalWeight = 0; 162 ArrayList<Double> weights = new ArrayList<>(); 163 if (nextLine[1].equals("必修")) { 164 if (nextLine.length != 5) { 165 System.out.println(nextLine[0] + " : number of scores does not match"); 166 return; 167 } 168 weightNumber = 2; 169 weights.add(Double.parseDouble(nextLine[3])); 170 weights.add(Double.parseDouble(nextLine[4])); 171 for (double weight:weights 172 ) { 173 totalWeight += weight; 174 } 175 } else if (nextLine[1].equals("选修")) { 176 weightNumber = 1; 177 totalWeight = 1; 178 weights.add(1.0); 179 } else if (nextLine[1].equals("实验")) { 180 weightNumber = Integer.parseInt(nextLine[3]); 181 if (nextLine.length != 4 + weightNumber) { 182 System.out.println(nextLine[0] + " : number of scores does not match"); 183 return; 184 } 185 if (!nextLine[3].matches("[4-9]")) { 186 System.out.println("wrong format"); 187 return; 188 } 189 for (int i = 4;i < nextLine.length;i ++) { 190 weights.add(Double.parseDouble(nextLine[i])); 191 totalWeight += Double.parseDouble(nextLine[i]); 192 } 193 } else { 194 System.out.println("wrong format"); 195 return; 196 } 197 if (Math.abs(totalWeight - 1) > 0.01) { 198 System.out.println(nextLine[0] + " : weight value error"); 199 return; 200 } 201 Course course = new Course(nextLine[0], nextLine[1], nextLine[2], weightNumber, weights); 202 if ((course.getcourseType().equals("必修") && !course.getAssessmentMethod().equals("考试")) || 203 (course.getcourseType().equals("实验") && !course.getAssessmentMethod().equals("实验"))) { 204 System.out.println(course.getCourseName() + " : course type & access mode mismatch"); 205 return; 206 } 207 courses.add(course); 208 } 209 public static void addScoredCourseSelection1(String[] nextLine, ArrayList<CourseSelection> courseSelections, ArrayList<Student> students, ArrayList<Course> courses) { 210 if (!nextLine[3].matches("100|[1-9][0-9]|[0-9]") || 211 !nextLine[4].matches("100|[1-9][0-9]|[0-9]") || 212 nextLine[0].length() != 8 || 213 nextLine[1].length() > 10) { 214 System.out.println("wrong format"); 215 return; 216 } 217 Student student = new Student(nextLine[0], nextLine[1]); 218 Iterator<Student> iterator = students.iterator(); 219 while (iterator.hasNext()) { 220 Student stu = iterator.next(); 221 if (stu.getstudentNumberID().equals(student.getstudentNumberID())) { 222 iterator.remove(); 223 } 224 } 225 students.add(student); 226 if (isCourseExist(nextLine[2], courses, nextLine.length, student)) { 227 for (Course course:courses 228 ) { 229 if (course.getCourseName().equals(nextLine[2])) { 230 Score score = new Score(new ExaminationResults(Integer.parseInt(nextLine[3]), Integer.parseInt(nextLine[4])), course); 231 CourseSelection courseSelection = new CourseSelection(course, student, score); 232 if (RepetitiveScores(courseSelection,courseSelections)) break; 233 courseSelections.add(courseSelection); 234 } 235 } 236 } 237 } 238 public static void addScoredCourseSelection2(String[] nextLine, ArrayList<Course> courses, ArrayList<Student> students, ArrayList<CourseSelection> courseSelections) { 239 if (!nextLine[3].matches("100|[1-9][0-9]|[0-9]") || 240 nextLine[0].length() != 8 || 241 nextLine[1].length() > 10) { 242 System.out.println("wrong format"); 243 return; 244 } 245 Student student = new Student(nextLine[0], nextLine[1]); 246 Iterator<Student> iterator = students.iterator(); 247 while (iterator.hasNext()) { 248 Student stu = iterator.next(); 249 if (stu.getstudentNumberID().equals(student.getstudentNumberID())) { 250 iterator.remove(); 251 } 252 } 253 students.add(student); 254 if (isCourseExist(nextLine[2], courses, nextLine.length, student)) { 255 for (Course course:courses 256 ) { 257 if (course.getCourseName().equals(nextLine[2])) { 258 Score score = new Score(new AssessmentResults(Integer.parseInt(nextLine[3])), course); 259 CourseSelection courseSelection = new CourseSelection(course, student, score); 260 if (RepetitiveScores(courseSelection,courseSelections)) break; 261 courseSelections.add(courseSelection); 262 } 263 } 264 } 265 } 266 public static void addScoredCourseSelection3(String[] nextLine, ArrayList<Course> courses, ArrayList<Student> students, ArrayList<CourseSelection> courseSelections) { 267 ArrayList<Integer> results = new ArrayList<>(); 268 if (nextLine[0].length() != 8 || nextLine[1].length() > 10) { 269 System.out.println("wrong format"); 270 return; 271 } 272 for (int i = 3;i < nextLine.length;i ++) { 273 if (!nextLine[i].matches("100|[1-9][0-9]|[0-9]")) { 274 System.out.println("wrong format"); 275 return; 276 } 277 results.add(Integer.parseInt(nextLine[i])); 278 } 279 Student student = new Student(nextLine[0], nextLine[1]); 280 Iterator<Student> iterator = students.iterator(); 281 while (iterator.hasNext()) { 282 Student stu = iterator.next(); 283 if (stu.getstudentNumberID().equals(student.getstudentNumberID())) { 284 iterator.remove(); 285 } 286 } 287 students.add(student); 288 if (isCourseExist(nextLine[2], courses, nextLine.length - 3, student)) { 289 for (Course course:courses 290 ) { 291 if (course.getCourseName().equals(nextLine[2])) { 292 Score score = new Score(new ExperimentalResults(results), course); 293 CourseSelection courseSelection = new CourseSelection(course, student, score); 294 if (RepetitiveScores(courseSelection,courseSelections)) break; 295 courseSelections.add(courseSelection); 296 } 297 } 298 } 299 } 300 } 301 302 class Course { 303 private String courseName; // 课程名称 304 private String courseType; // 课程性质 305 private String AssessmentMethod; // 考核方式 306 private int weightNumber; 307 private ArrayList<Double> weight; 308 309 public Course(String courseName, String courseType, String assessmentMethod, int weightNumber, ArrayList<Double> weight) { 310 this.courseName = courseName; 311 this.courseType = courseType; 312 AssessmentMethod = assessmentMethod; 313 this.weightNumber = weightNumber; 314 this.weight = weight; 315 } 316 317 public String getCourseName() { 318 return courseName; 319 } 320 321 /* public void setCourseName(String courseName) { 322 this.courseName = courseName; 323 }*/ 324 325 public String getcourseType() { 326 return courseType; 327 } 328 329 /* public void setcourseType(String courseType) { 330 this.courseType = courseType; 331 }*/ 332 333 public String getAssessmentMethod() { 334 return AssessmentMethod; 335 } 336 337 /* public void setAssessmentMethod(String assessmentMethod) { 338 AssessmentMethod = assessmentMethod; 339 }*/ 340 341 public int getWeightNumber() { 342 return weightNumber; 343 } 344 345 /* public void setWeightNumber(int weightNumber) { 346 this.weightNumber = weightNumber; 347 }*/ 348 349 public ArrayList<Double> getWeight() { 350 return weight; 351 } 352 353 /* public void setWeight(ArrayList<Double> weight) { 354 this.weight = weight; 355 }*/ 356 } 357 358 class Score { 359 private ExaminationResults examinationResults; 360 private AssessmentResults assessmentResults; 361 private ExperimentalResults experimentalResults; 362 private Course course; 363 364 public Score(ExaminationResults examinationResults, Course course) { 365 this.examinationResults = examinationResults; 366 this.course = course; 367 } 368 369 public Score(AssessmentResults assessmentResults, Course course) { 370 this.assessmentResults = assessmentResults; 371 this.course = course; 372 } 373 374 public Score(ExperimentalResults experimentalResults, Course course) { 375 this.experimentalResults = experimentalResults; 376 this.course = course; 377 } 378 379 public int getTotalScore() { 380 if (course.getAssessmentMethod().equals("考试")) { 381 return (int) (examinationResults.getDailyPerformance() * course.getWeight().get(0) + examinationResults.getFinalGrade() * course.getWeight().get(1)); 382 } else if (course.getAssessmentMethod().equals("考察")) { 383 return assessmentResults.getTotalScore(); 384 } else { 385 double totalScore = 0; 386 int i = 0; 387 for (int result:experimentalResults.getResults() 388 ) { 389 totalScore += result * course.getWeight().get(i); 390 i ++; 391 } 392 return (int) (totalScore); 393 } 394 } 395 } 396 class ExaminationResults { 397 398 private int dailyPerformance; 399 private int finalGrade; 400 public ExaminationResults(int dailyPerformance, int finalGrade) { 401 this.dailyPerformance = dailyPerformance; 402 this.finalGrade = finalGrade; 403 } 404 405 public int getDailyPerformance() { 406 return dailyPerformance; 407 } 408 409 /* public void setDailyPerformance(int dailyPerformance) { 410 this.dailyPerformance = dailyPerformance; 411 }*/ 412 413 public int getFinalGrade() { 414 return finalGrade; 415 } 416 417 /* public void setFinalGrade(int finalGrade) { 418 this.finalGrade = finalGrade; 419 }*/ 420 } 421 422 class AssessmentResults { 423 private int totalScore; 424 425 public int getTotalScore() { 426 return totalScore; 427 } 428 429 /* public void setTotalScore(int totalScore) { 430 this.totalScore = totalScore; 431 }*/ 432 433 public AssessmentResults(int totalScore) { 434 this.totalScore = totalScore; 435 } 436 } 437 438 class ExperimentalResults { 439 private ArrayList<Integer> results = new ArrayList<>(); 440 public ExperimentalResults(ArrayList<Integer> results) { 441 this.results = results; 442 } 443 444 public ArrayList<Integer> getResults() { 445 return results; 446 } 447 448 /* public void setResults(ArrayList<Integer> results) { 449 this.results = results; 450 }*/ 451 } 452 453 454 class Student { 455 private String studentNumberID; 456 private String studentName; 457 458 public Student(String studentNumberID, String studentName) { 459 this.studentNumberID = studentNumberID; 460 this.studentName = studentName; 461 } 462 463 public String getstudentNumberID() { 464 return studentNumberID; 465 } 466 467 public void setstudentNumberID(String studentNumberID) { 468 this.studentNumberID = studentNumberID; 469 } 470 471 public String getStudentName() { 472 return studentName; 473 } 474 } 475 476 class PersonOverride { 477 private String name; 478 private int age; 479 private boolean gender; 480 481 public PersonOverride(String name, int age, boolean gender) { 482 this.name = name; 483 this.age = age; 484 this.gender = gender; 485 } 486 487 public PersonOverride() { 488 489 this("default", 1, true); 490 491 } 492 493 @Override 494 public String toString() { 495 496 return name + "-" + age + "-" + gender; 497 498 } 499 500 @Override 501 public boolean equals(Object obj) { 502 if (obj == this) { 503 return true; 504 } 505 if (!(obj instanceof PersonOverride)) { 506 return false; 507 } 508 PersonOverride other = (PersonOverride) obj; 509 return this.name.equals(other.name) && this.age == other.age && this.gender == other.gender; 510 } 511 } 512 513 class TotalScore{ 514 515 } 516 class Class { 517 518 private int classNumber; 519 private int classAverageScore; 520 private ArrayList<Student> students = new ArrayList<>(); 521 522 /* public Class(int classNumber, ArrayList<Student> students) { 523 this.classNumber = classNumber; 524 this.students = students; 525 }*/ 526 527 public Class() { 528 529 } 530 531 public int getClassAverageScore() { 532 return classAverageScore; 533 } 534 535 public void setClassAverageScore(int classAverageScore) { 536 this.classAverageScore = classAverageScore; 537 } 538 539 public int getClassNumber() { 540 return classNumber; 541 } 542 543 public void setClassNumber(int classNumber) { 544 this.classNumber = classNumber; 545 } 546 547 public ArrayList<Student> getStudents() { 548 return students; 549 } 550 551 /* public void setStudents(ArrayList<Student> students) { 552 this.students = students; 553 } 554 public void addStudent(Student student) { 555 students.add(student); 556 }*/ 557 } 558 class CourseSelection { 559 private Course course; 560 private Student student; 561 private Score score; 562 563 public CourseSelection(Course course, Student student, Score score) { 564 this.course = course; 565 this.student = student; 566 this.score = score; 567 } 568 569 public Course getCourse() { 570 return course; 571 } 572 573 /* public void setCourse(Course course) { 574 this.course = course; 575 }*/ 576 577 public Student getStudent() { 578 return student; 579 } 580 581 /* public void setStudent(Student student) { 582 this.student = student; 583 }*/ 584 585 public Score getScore() { 586 return score; 587 } 588 589 /* public void setScore(Score score) { 590 this.score = score; 591 }*/ 592 }
类图:
同上一次的课程成绩统计程序-2一样,同样是因为浮点误差没能够得到更多的份数。
期末考试:
从7-1立体图形问题到7-3魔方排序问题同样是一个依次升级的问题,但总体上的框架相似。
7-2魔方问题:
问题描述:本问题中的魔方有两种,一种是正方体魔方,一种是正三棱锥魔方,其中,正方体或正三棱锥魔方是由单元正方体或正三棱锥组成,单元正方体或正三棱锥的个数由阶数(即层数)决定,即魔方边长=阶数*单元边长。魔方如下图所示:
利用“立体图形”问题源码,实现如下功能:
魔方有三个属性:颜色,阶数,类型(正方体魔方、正三棱锥魔方),程序要求输出魔方的颜色、表面积和体积。参考设计类图如下所示:
主方法部分可参考如下源码(可拷贝直接使用):
public class Main {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input = new Scanner(System.in);
String color = input.next();
int layer = input.nextInt();
double side = input.nextDouble();
RubikCube cube1 = new SquareCube(color, layer,new Cube(side));
color = input.next();
layer = input.nextInt();
side = input.nextDouble();
RubikCube cube2 = new RegularPyramidCube(color, layer,new RegularPyramid(side));
display(cube1);
display(cube2);
}
}
其中,display(RubikCube cube)方法为Main类中定义的静态方法,用户输出魔方的信息,用于体现多态性。
输入格式:
第一部分:正方体魔方颜色、阶数、单元正方体边长,以空格或回车分隔;
第二部分:正三棱锥魔方颜色、阶数、单元正三棱锥边长,以空格或回车分隔。
输出格式:
正方体魔方颜色
正方体魔方表面积
正方体魔方体积
正三棱锥魔方颜色
正三棱锥魔方表面积
正三棱锥魔方体积
注:小数点保留两位
输入样例:
在这里给出一组输入。例如:
red 3 4.5
black 4 2.1
输出样例:
在这里给出相应的输出。例如:
red
1093.50
2460.38
black
122.21
69.85
源代码:
1 import java.util.Scanner; 2 3 public class Main { 4 public static void main(String[] args) { 5 // TODO Auto-generated method stub 6 Scanner input = new Scanner(System.in); 7 8 String color = input.next(); 9 int layer = input.nextInt(); 10 double side = input.nextDouble(); 11 12 RubikCube cube1 = new SquareCube(color, layer, new Cube(side)); 13 14 color = input.next(); 15 layer = input.nextInt(); 16 side = input.nextDouble(); 17 18 RubikCube cube2 = new RegularPyramidCube(color, layer, new RegularPyramid(side)); 19 display(cube1); 20 display(cube2); 21 } 22 23 public static void display(RubikCube cube) { 24 System.out.println(cube.getColor()); 25 System.out.println(String.format("%.2f", cube.surfaceArea())); 26 System.out.println(String.format("%.2f", cube.volume())); 27 } 28 } 29 30 interface Solid { 31 double surfaceArea(); 32 double volume(); 33 } 34 35 class Cube implements Solid { 36 private double side; 37 public Cube(double side) { 38 this.side = side; 39 } 40 41 @Override 42 public double surfaceArea() { 43 return 6 * side * side; 44 } 45 46 @Override 47 public double volume() { 48 return side * side * side; 49 } 50 } 51 52 class RegularPyramid implements Solid { 53 private double side; 54 public RegularPyramid(double side) { 55 this.side = side; 56 } 57 58 @Override 59 public double surfaceArea() { 60 return (side/2)*(side/2)*Math.sqrt(3)*4; 61 } 62 63 @Override 64 public double volume() { 65 return side * Math.sqrt(6) * side * side * Math.sqrt(3) / 36; 66 } 67 } 68 69 abstract class RubikCube { 70 protected String color; 71 protected int layer; 72 protected Solid unit; 73 74 public RubikCube(String color, int layer, Solid unit) { 75 this.color = color; 76 this.layer = layer; 77 this.unit = unit; 78 } 79 80 public String getColor() { 81 return color; 82 } 83 84 public abstract double surfaceArea(); 85 86 public abstract double volume(); 87 } 88 89 class SquareCube extends RubikCube { 90 public SquareCube(String color, int layer, Solid unit) { 91 super(color, layer, unit); 92 } 93 94 @Override 95 public double surfaceArea() { 96 return layer * layer * unit.surfaceArea(); 97 } 98 99 @Override 100 public double volume() { 101 return layer * layer * layer * unit.volume(); 102 } 103 } 104 105 class RegularPyramidCube extends RubikCube { 106 public RegularPyramidCube(String color, int layer, Solid unit) { 107 super(color, layer, unit); 108 } 109 110 @Override 111 public double surfaceArea() { 112 return layer * layer * unit.surfaceArea(); 113 } 114 115 @Override 116 public double volume() { 117 return layer * layer * layer * unit.volume(); 118 } 119 }
三.踩坑心得
在第7、8次PTA作业中遇到的问题主要来自于输出结果匹配,基本的类方法可以按照题目给出的类图来构建,主要的难点则在于计算成绩的相应算法,因为加入了实验课、课程权重等因素,总成绩的计算过程相对复杂,这就很考验自己的算法设计,另外就是我提了两次的浮点误差问题很难解决。
四.主要困难与改进意见
可以在函数的命名等方面加强练习,现在就会遇到当时为了好尽快完成代码随意命名,后来改正的时候修改代码不理解变量的对应关系。
五.总结
这是这学期java的最后一次博客了,在这门语言刚开始的时候我真的感觉到了较大的困难,特别是代码量增加时,当时完全不理解所谓的面向对象,不知道代码应该怎么去开始,但在系统学习了相关知识并且自己学习了基础操作后,通过摸索以及训练完成一系列任务,在很多情况下确实比单纯的c语言有很大的优势。现在学习了一系列的模式之后,更是体会到了使用面向对象编程的优势。但是自己在面对长代码的时候,基本上都得依靠题目给出的类图,很多情况都没能独立思考到,这方面还有很多知识需要学习。
标签:nextLine,JAVA,int,ArrayList,南昌,Blog,course,return,public From: https://www.cnblogs.com/nchu212072lyt/p/17889055.html