如何定位這個java while循環？

Question

所以while循環不起作用，即使它編譯。我如何正確定位？

我嘗試了一些東西，但他們有點工作。如果有人在這裏可以幫助我走出這將是巨大

import java.util.Scanner; 
//This is a Driver program to test the external Class named Student 
public class StudentDriver //BEGIN Class Definition 
{ 
    //**************** Main Method************************* 
    public static void main (String[] args) 
    {Scanner scan = new Scanner(System.in); 
    //Data Definitions: 
    //Instance Data 
    String courseName; 
    int courseCredits; 

    String name; 
    String id; 
    String street; 
    String city; 
    String state; 
    String zip; 
    String major; 

    //Executable Statements: 
    //Initialize first Student 
    name = "Fred Fergel"; 
    id = "0123"; 
    street = "123 Main Street"; 
    city = "Smalltown"; 
    state = "NY"; 
    zip = "12345"; 
    major = "Computer Science"; 
    //instantiate the Student object 
    Student student1 = new Student(name, id, street, city, state, zip, major); 
    //Test toString 
    System.out.println("Student 1\n\n" + student1.toString()); 
    //Print a blank line 
    System.out.println(); 
    //Add a course 
    student1.addCourse("CSC111", 4);//NOTE:  DO NOT PUT A SPACE BETWEEN CSC AND 111 
    //Print schedule 
    System.out.println("Student 1's Schedule:\n\n"); 
    student1.displaySchedule();//call method 

    final String FLAG = "Y"; 
    String prompt = "Y"; 
    while (prompt.equals("y")) 
    { 
    System.out.println("Please enter the name of the course: "); 
    courseName = scan.next(); 
    System.out.println("How many credits is the course? "); 
    courseCredits = scan.nextInt(); 
    student1.addCourse(courseName, courseCredits); 
    System.out.println("Do you wish to enter another course? y/n"); 
    prompt = scan.next(); 
    } 
    //end while 


    }//end main 
}//end StudentDriver 

這裏是學生類：

import java.util.Scanner; 
public class Student 
{Scanner scan = new Scanner(System.in); 
    //Instance Data 
    String studentName; 
    String studentID; 
    String streetAddress; 
    String city; 
    String state; 
    String zipCode; 
    String major; 
    int totalCredits; 
    final int SIZE = 6; 
    final int MAX_CREDITS = 18; 
    String [ ] schedule = new String [SIZE]; 
    int courseNumber = 0; //start out with no courses 
    //Create Constructor: 
    //Initializes the student data at instantiation time. 
    //------------------------------------------------------- 
    // Sets up the student's information. 
    //------------------------------------------------------- 
    public Student (String name, String id, String address, String cityName, String stateName, String zip, String area) 
    { 
    studentName = name; 
    studentID = id; 
    streetAddress = address; 
    city = cityName; 
    state = stateName; 
    zipCode = zip; 
    major = area; 
    }//end Student Constructor 
    //Method to Return student information as string: 
    //------------------------------------------------------- 
    // Returns the student information as a formatted string. 
    //------------------------------------------------------- 
    public String toString() 
    { 
    String studentInfo; 
    studentInfo = "Name:\t\t\t" + studentName + "\n" + "ID:\t\t\t" + studentID + "\n" + "Address:\t\t" + streetAddress 
    + "\n" + "City:\t\t\t" + city + "\n" + "State:\t\t\t" + state + "\n" + "Zip Code:\t\t" + zipCode 
    + "\n" + "Major:\t\t\t" + major + "\n"; 
    return studentInfo; 
}// end toString 
    //Method to determine if maximum allowed credits have been exceeded 
    //------------------------------------------------------- 
    // Returns true if total credits does not exceed 18. 
    //------------------------------------------------------- 
    private boolean checkCredits(int numCredits) 
    { 
    if (numCredits + totalCredits <= MAX_CREDITS) //make sure max credits not exceeded 
    { 
    return true; //return a true if still less than 18 credits 
        } 
    else 
    { 
    return false; //return a false if 18 credit limit is exceeded 
    }//end numCredits 
    }//checkCredits 
    //Method to add a course to the student’s schedule 
    //------------------------------------------------------- 
    // Adds a course to the array if total credits does not exceed 18. 
    //------------------------------------------------------- 
    public void addCourse(String course, int numCredits) 
    { 
    if (courseNumber < SIZE) //make sure array is not full. 
    { 
    if (checkCredits(numCredits) == true) //if we’re under 18 credits 
    { 
    //add course 
    schedule [courseNumber] = course + ":\t\t" + numCredits + "\tCredits\n"; 
    //increment number of credits 
    totalCredits = totalCredits + numCredits; 
    //increment number of courses 
    courseNumber = courseNumber + 1; 
    } 
    else //oops – can’t do more than 18 credits 
    { 
    System.out.println("You have exceeded the maximum allowed credits."); 
    }//end checkCredits 
    } 
    else //oops – can’t do more than 10 courses 
    { 
    System.out.println("You have exceeded 10 courses."); 
    }//end courseNumber 
    }//addCourse 
    //Method to display the schedule 
    //------------------------------------------------------- 
    // Will only print out the courses added to the array. 
    //------------------------------------------------------- 
    public void displaySchedule() 
    { 
    for (int index = 0; index < courseNumber; index++) 
    { 
    System.out.println("Course #" + (index + 1) + " " + schedule[index] + "\n"); 
    }//end for 
    }//end display schedule 

} 

Answer 1

String prompt = "Y"; 
while (prompt.equals("y")) 

Y和y是不一樣的東西。如果您希望忽略大小寫，則需要使用.equalsIgnoreCase()而不是.equals()。