【发布时间】：2013-12-01 01:26:36
【问题描述】：
行号为here的代码
package project5_test2;
import java.util.ArrayList;
import java.util.InputMismatchException;
import java.util.Scanner;
/**
*
* @author David
*/
public class Project5_test2 {
public static Object Student;
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
// TODO code application logic here
Scanner input = new Scanner(System.in);
// initialize an arary that holds N objects of type Student
int end = 1;
ArrayList<Student> studentList = new ArrayList<>();
// read in the data
for (int y = 0; y < end;) {
String nextMove = nextMove();
for (int i = 0; i < end;) {
if ("add".equalsIgnoreCase(nextMove)) {
System.out.println("Student Input: ");
String firstName = getFirstName();
String lastName = getLastName();
int uid = getUid();
String stringUid = Integer.toString(uid);
StudentType type = inputStudentType();
if (type == StudentType.UNDECLARED) {
ClassStanding standing = inputClassStanding();
studentList.add(new Student(firstName, lastName, uid, type, standing ));
}
if (type == StudentType.UNDERGRADUATE) {
ClassStanding standing = inputClassStanding();
Major major = inputMajor();
double overallGpa = getOverallGPA();
String overallGpaDouble = Double.toString(overallGpa);
double majorGpa = getOverallGPA();
String majorGpaDouble = Double.toString(majorGpa);
studentList.add(new Student(firstName, lastName, uid, type, standing));
}
if (type == StudentType.GRADUATE) {
boolean thesis = getThesisStatus();
String thesisString = Boolean.toString(thesis);
ClassStanding studyType = getStudy();
String profName = getProfName();
studentList.add(new Student.Graduate( thesis, studyType, profName));
}
} i++;
}
if ("remove".equalsIgnoreCase(nextMove)) {
System.out.println("derp");
}
if ("save".equalsIgnoreCase(nextMove)) {
for (int i = 0; i < studentList.size(); i++) {
System.out.println(studentList.get(i));
}
y++;
}
}
}
enum ClassStanding {
FRESHMAN, SOPHOMORE, JUNIOR, SENIOR, UNKNOWN,
MASTERS_STUDIES, PHD_STUDIES, NO_STANDING
};
enum StudentType {
UNDERGRADUATE, GRADUATE, UNDECLARED
};
enum Major {
CS, CEG, EE, ISE, BME, ME, MET, UNKNOWN
};
public static class Student {
public String firstName; // first name
public String lastName;
public double uid; // last name
public StudentType type;
public ClassStanding standing;
public Student(Student orig) {
}
// construct a new student with given fields
public Student(String firstName, String lastName, Integer newUid, StudentType type, ClassStanding standing) {
this.firstName = firstName;
this.lastName = lastName;
this.uid = newUid;
this.type = type;
this.standing = standing;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getFirstName() {
return firstName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getLastName() {
return lastName;
}
//set type
public void setType(StudentType type) {
this.type = type;
}
//return type
public StudentType getType() {
return type;
}
public void setStanding(ClassStanding standing) {
this.standing = standing;
}
//return type
public ClassStanding getStanding() {
return standing;
}
// return a string representation of the invoking object
public String toString() {
return firstName + " " + lastName + " " + uid + " " + type + " " + standing;
}
public static class Graduate extends Student {
public boolean thesis;
public ClassStanding study;
public String profName;
public Graduate(Student orig, boolean isThesis, ClassStanding study, String profName) {
super(orig);
}
public boolean getThesis() {
return thesis;
}
public void setThesis(Boolean thesis) {
this.thesis = thesis;
}
public ClassStanding getStudy() {
return study;
}
public void setStudy(ClassStanding study) {
this.study = study;
}
public String getProfName() {
return profName;
}
public void setProfName(String profName) {
this.profName = profName;
}
public String toString() {
return thesis + " " + study + " " + profName;
}
}
public static class UnderGraduate extends Student {
public Major major;
public Double GPA;
public UnderGraduate(Student orig, Major major, Double GPA) {
super(orig);
}
public void setMajor(Major major) {
this.major = major;
}
//return type
public Major getmMajor() {
return major;
}
public void setOverallGPA(Integer uid) {
this.uid = uid;
}
public double getOverallGPA() {
return uid;
}
public String toString() {
return major + " " + uid ;
}
}
}
public static String getFirstName() {
Scanner input = new Scanner(System.in);
String firstName;
while (true) {
//prompt the user to enter the popularity number for each character
try {
System.out.print("Please enter the students first name: ");
firstName = input.next();
break;
//error handling
} catch (InputMismatchException e) {
System.out.println("Not a string please enter another first name!");
input.next();
continue;
}
}
return firstName;
}
public static String getLastName() {
Scanner input = new Scanner(System.in);
String lastName;
while (true) {
//prompt the user to enter the popularity number for each character
try {
System.out.print("Please enter a students last name: ");
lastName = input.next();
break;
//error handling
} catch (InputMismatchException e) {
System.out.println("Not a string please enter another last name!");
input.next();
continue;
}
}
return lastName;
}
public static Integer getUid() {
Scanner input = new Scanner(System.in);
int uid;
while (true) {
//prompt the user to enter the popularity number for each character
try {
System.out.print("Please enter a uid number: ");
uid = input.nextInt();
break;
//error handling
} catch (InputMismatchException e) {
System.out.println("Not a number or an integer!");
input.next();
continue;
}
}
return uid;
}
public static StudentType inputStudentType() {
Scanner input = new Scanner(System.in);
String type;
while (true) {
//prompt the user to enter the popularity number for each character
try {
System.out.print("Is the student a graduate, undergraduate, or, undeclared: ");
type = input.next();
break;
//error handling
} catch (InputMismatchException e) {
System.out.println("False input. Is the student a graduate, undergraduate, or, undeclared: ");
type = input.next();
continue;
}
}
if ("undergraduate".equalsIgnoreCase(type)) {
StudentType status = StudentType.UNDERGRADUATE;
return status;
}
if ("graduate".equalsIgnoreCase(type)) {
StudentType status = StudentType.GRADUATE;
return status;
}
if ("undeclared".equalsIgnoreCase(type)) {
StudentType status = StudentType.UNDECLARED;
return status;
}
return null;
}
public static String nextMove() {
Scanner input = new Scanner(System.in);
String nextMove;
while (true) {
// prompt the user to enter if there are more characers
try {
System.out.print("What now? Add, Sort, Remove, Save: ");
nextMove = input.next();
break;
//error handling
} catch (InputMismatchException e) {
System.out.println("More input? true or false(type true or false): ");
input.next();
continue;
}
}
return nextMove;
}
public static ClassStanding inputClassStanding() {
Scanner input = new Scanner(System.in);
String type;
while (true) {
//prompt the user to enter the popularity number for each character
try {
System.out.print("Enter the students class standing: ");
type = input.next();
break;
//error handling
} catch (InputMismatchException e) {
System.out.println("False input. Input the students class standing: ");
type = input.next();
continue;
}
}
if ("Freshman".equalsIgnoreCase(type)) {
ClassStanding standing = ClassStanding.FRESHMAN;
return standing;
}
if ("sophomore".equalsIgnoreCase(type)) {
ClassStanding standing = ClassStanding.SOPHOMORE;
return standing;
}
if ("junior".equalsIgnoreCase(type)) {
ClassStanding standing = ClassStanding.JUNIOR;
return standing;
}
if ("senior".equalsIgnoreCase(type)) {
ClassStanding standing = ClassStanding.SENIOR;
return standing;
}
if ("unknown".equalsIgnoreCase(type)) {
ClassStanding standing = ClassStanding.UNKNOWN;
return standing;
}
return null;
}
public static Major inputMajor() {
Scanner input = new Scanner(System.in);
String major;
while (true) {
//prompt the user to enter the popularity number for each character
try {
System.out.print("Enter the students major (CS, CEG, EE, ISE, BME, ME, MET, UNKNOWN): ");
major = input.next();
break;
//error handling
} catch (InputMismatchException e) {
System.out.println("False input. Enter the students major (CS, CEG, EE, ISE, BME, ME, MET, UNKNOWN): ");
major = input.next();
continue;
}
}
if ("cs".equalsIgnoreCase(major)) {
Major finalMajor = Major.CS;
return finalMajor;
}
if ("ceg".equalsIgnoreCase(major)) {
Major finalMajor = Major.CEG;
return finalMajor;
}
if ("ee".equalsIgnoreCase(major)) {
Major finalMajor = Major.EE;
return finalMajor;
}
if ("ise".equalsIgnoreCase(major)) {
Major finalMajor = Major.ISE;
return finalMajor;
}
if ("bme".equalsIgnoreCase(major)) {
Major finalMajor = Major.BME;
return finalMajor;
}
if ("ME".equalsIgnoreCase(major)) {
Major finalMajor = Major.ME;
return finalMajor;
}
if ("met".equalsIgnoreCase(major)) {
Major finalMajor = Major.MET;
return finalMajor;
}
if ("unknown".equalsIgnoreCase(major)) {
Major finalMajor = Major.UNKNOWN;
return finalMajor;
}
return null;
}
public static Double getOverallGPA() {
Scanner input = new Scanner(System.in);
double overallGpa;
while (true) {
//prompt the user to enter the popularity number for each character
try {
System.out.print("Please enter the students overall GPA: ");
overallGpa = input.nextDouble();
break;
//error handling
} catch (InputMismatchException e) {
System.out.println("Not a number or an integer! Please enter the students overall GPA:");
input.next();
continue;
}
}
return overallGpa;
}
public static Double getMajorlGPA() {
Scanner input = new Scanner(System.in);
double majorGpa;
while (true) {
//prompt the user to enter the popularity number for each character
try {
System.out.print("Please enter the students major GPA: ");
majorGpa = input.nextDouble();
break;
//error handling
} catch (InputMismatchException e) {
System.out.println("Not a number or an integer! Please enter the students major GPA:");
input.next();
continue;
}
}
return majorGpa;
}
public static boolean getThesisStatus() {
Boolean thesis;
Scanner input = new Scanner(System.in);
while (true) {
//prompt the user to enter the popularity number for each character
try {
System.out.print("Enter TRUE for having a thesis option else FALSE: ");
thesis = input.nextBoolean();
break;
//error handling
} catch (InputMismatchException e) {
System.out.println("Not a boolean response. True or false, is there a thesis: ");
input.next();
continue;
}
}
return thesis;
}
public static ClassStanding getStudy() {
String study = null;
Scanner input = new Scanner(System.in);
for (int i = 0; i < 1;) {
while (true) {
//prompt the user to enter the popularity number for each character
try {
System.out.print("Enter Masters for Master Studies or Phd for Phd studies: ");
study = input.next();
break;
//error handling
} catch (InputMismatchException e) {
System.out.println("Not a valid response. Enter Masters for Master Studies or Phd for Phd studies: ");
input.next();
continue;
}
}
if ("masters".equalsIgnoreCase(study)) {
ClassStanding standing = ClassStanding.MASTERS_STUDIES;
return standing;
}
if ("phd".equalsIgnoreCase(study)) {
ClassStanding standing = ClassStanding.PHD_STUDIES;
return standing;
}
}
return null;
}
public static String getProfName() {
String name;
Scanner input = new Scanner(System.in);
while (true) {
//prompt the user to enter the popularity number for each character
try {
System.out.print("Enter the name of the major professor: ");
name = input.next();
break;
//error handling
} catch (InputMismatchException e) {
System.out.println("Not a valid response. Enter the name of the major professor: ");
input.next();
continue;
}
}
return name;
}
}
问题目前显示在第 54 行，同样的错误将出现在第 46 行。
写入 ArrayList studentList 时，我需要包含一个 Student 类型的变量。
这个问题可能出现在我的子类的构造函数中，但我对子类并不完全熟悉。
【问题讨论】：
-
如果你没有在里面做任何事情，为什么你需要
public Student(Student orig) { }构造函数？它应该是复制构造函数吗？ -
我不确定，但我相信。行 studentList.add(new Student.Graduate( xxxxxxxxxx , thesis, studyType, profName)); xxxxxx 缺失，需要是学生类型。我该怎么做。它可能与未使用的构造函数有关。
-
我一直讨厌方法太长，以至于您必须滚动才能看到它们的完整主体（许多其他人就像我一样）。将这么长的方法分解成单独的方法，正确命名每个方法，这样您的代码将更具可读性，并且每个人都可以更轻松、更多地帮助您。
标签： java class inheritance arraylist subclass