integer inputs will not save apart from the first

[David Ausere]

I have create a program that you enter student information in.  I think I have all the code right, but when I enter the informantion and then choose option "2" to print out the information entered the integer inputs all come back "0" apart from "StudentID'.  Can someone show me where I have gone wrong and what I need to do to fix it?

import java.util.*;

public class Student
{
    private int ID;
    private String fname;
    private String lname;
    private String email;
    private int age;
    private int grade1;
    private int grade2;
    private int grade3;

    public Student( int StudentID, String Firstname, String Lastname, String Email, int age, int grade1, int grade2, int grade3 )
    {
        ID = StudentID;
        fname = Firstname;
        lname = Lastname;
        email = Email;
        age = age;
        grade1 = grade1;
        grade1 = grade2;
        grade1 = grade3;
        
    }

    public int getStudentID()
    {
        return ID;
    }
 
    public String getFirstname()
    {
        return fname;
    }
    
    public String getLastname()
    {
        return lname;
    }
  
    public String getEmail()
    {
        return email;
    }
   
    public int getAge()
    {
        return age;
    }

    public int getgrade1()
    {
        return grade1;
    }

    public int getgrade2()
    {
        return grade2;
    }

    public int getgrade3()
    {
        return grade3;
    }
    
       public String toString()
    {
        return " Student ID " + ID + " First name: " + fname + " Last name: " + lname + " Email: " + email + " age: " + age + 
               " Grade 1: " + grade1 + " Grade 2: " + grade2 +
               " Grade 3: " + grade3;
    }

    public static void main(String[] args) 
    {
       ArrayList<Student> Roster = new ArrayList<Student>();
       Scanner input = new Scanner(System.in);

       int menuChoice = 4;
       do {
           System.out.println("\t\t\tStudent Record Menu");
           System.out.println("\t\t1. Add Student\t2. View Students\t3. Search Student\t4. Exit");
           try {
               System.out.println("Enter a choice: ");
               menuChoice = Integer.parseInt(input.nextLine());
           } catch (NumberFormatException e) {
               continue;
           }

           if (menuChoice==1)
           {
               int ID = 0;
               System.out.println("StudentID: ");
               ID = Integer.parseInt(input.nextLine());
               
               System.out.println("First name: ");
               String Fname = input.nextLine();
               
               System.out.println("Last name: ");
               String Lname = input.nextLine();
               
               System.out.println("Email: ");
               String Email = input.nextLine();

               int Age = 0;
               System.out.println("Age: ");
               Age = Integer.parseInt(input.nextLine());
               
               int Grade1 = 0;
               System.out.println("Grade 1: ");
               Grade1 = Integer.parseInt(input.nextLine());

               int Grade2 = 0;
               System.out.println("Grade 2: ");
               Grade2 = Integer.parseInt(input.nextLine());

               int Grade3 = 0;
               System.out.println("Grade 3: ");
               Grade3 = Integer.parseInt(input.nextLine());

               Student students = new Student (ID, Fname, Lname, Email, Age, Grade1, Grade2, Grade3);
               Roster.add(students);

           } else if (menuChoice==2) {
               System.out.println("Students: ");
               for (Student students : Roster)
               {
                   System.out.println(students);
               }
           }
       } while (menuChoice<4);
    }
}

[Henry Wong]

Take a look at your constructor ... and question... what happens when you have a local variable with the same name as an instance variable?

Henry

[Liutauras Vilda]

To addition to Henry's reply, you also slipped on copy/paste error. All grades get assigned to grade1, hence overriding previous grade.

[Liutauras Vilda]

In order to reduce headache thinking synonym for parameters and fields - use 'this'. i.e.:

public class Example {
    private String email;

    public Exampe (String email) {
        this.email = email
    }
}

'this' referring to an instance variable, which is on line 2.

[David Ausere]

I see where I went wrong and got it fixed!  Thank you!

Any pointers on an easy way to make the Student ID autopopulate for each addition?

[Liutauras Vilda]

David Ausere wrote:Any pointers on an easy way to make the Student ID autopopulate for each addition?

Have this field as a static and increment (within constructor) each time an object of a Student class is created.
Probably this is what your teacher is expecting at an academic level.

[Campbell Ritchie]

Welcome to the Ranch and well done understanding the hint about your problem.
A few style things:-

1: A few of your lines are too long. Line 14 would read better as in the code below: this is how you can deal with such long lines.

2: Where you have two different names for the parameter and the field in a constructor (or a set method), give them the same name, as in my version of your constructor below. That way, you can display the best name as a parameter, and use the best name for a field. Note the construct with this.xxx. That means the field called xxx rather than the local variable/parameter xxx. You may be able to improve those field names without my help.

3: You have the Capitalletters in the wrong places in that constructor. Not Lastname but lastName please.

4: No space after ( on line 14 please.

5: There is no need for an empty line at line 24: I have removed it.

6: Your getXXX methods should have a Capital Letter after get: getGrade1 rather than getgrade1 please.

public Student(int studentID, String firstName, String lastName,               String email, int age, int grade1, int grade2, int grade3 ) {    this.StudentID = studentID;    this.firstName = firstName;    this.lastName = lastName;    this.email = email;    this.age = age;    this.grade1 = grade1;    this.grade1 = grade2;    this.grade1 = grade3; }Line 69 could also benefit from breaking into several lines.