CODEWITHSUNDEEP
javaarraylist
Sarid Ruiz
Sarid Ruiz

Reputation: 43

Creating an ArrayList in a user defined class Java

I've been searching every where but couldn't find an answer.

I'm trying to make an ArrayList to store 10 grades in a user defined class so I can then call it in the Client class and input the grades with a Scanner(System.in) and then output them all together but I don't know if its possible to do it and I've searched everywhere for an answer. Please Help.

This is what I have so far of my user defined class

import java.util.ArrayList;

public class Student {

private String student;
private String courseName;
private double grade;
private double avg;
private double total;
private double max;
private double min;

//Constructor w/o arguments
public Student() {
    this.student = "";
    this.courseName = "";
    this.grade = 0.0;
}

//Constructor with arguments
public Student(String student, String courseName, double grade, double avg, double total, double max, double min) {
    this.student = student;
    this.courseName = courseName;
    this.grade = grade;
}

//Getters
public String getStudent(){
    return this.student;
}
public String getCourseName() {
    return this.courseName;
}


//Setters
public void setStudent(String student) {
    this.student = student;
}
public void setCourseName(String courseName) {
    this.courseName = courseName;
}


//Returns average off the 10 grades
public double calculateAvg() {
    total += grade; //add all grades for average
    avg = total / 10;
    return avg;
}

//Highest Grade
public double highGrade() {
    return max = Math.max(grade, max);
}
//Lowest Grade
public double lowGrade() {
    return min = Math.min(grade, min);
}

ArrayList<Student>listGrades = new ArrayList<Student>();

Upvotes: 0

Views: 2638

Answers (3)

Gagan
Gagan

Reputation: 296

You should try something like this.

public static void main(String[] args) {
            System.out.println("Enter number of Students :");
            Scanner scanner = new Scanner(System.in); 
            Student s=new Student("gagan","Math",0.0d,0.0d, 0.0d, 0.0d,0.0d);
            s.listGrades.add(s);

            for(Student s1:s.listGrades) {
                System.out.println("Enter Grade for student"+s.getStudent()+": ");
                s1.setGrade(scanner.nextDouble());
            }
            scanner.close();


        }

Upvotes: 0

Laura Liparulo
Laura Liparulo

Reputation: 2907

Initialize it in a constructor or another method: [https://www.geeksforgeeks.org/initialize-an-arraylist-in-java/][1]

Upvotes: 0

gervais.b
gervais.b

Reputation: 2347

Not sure to understand what you want but that will do it :

class Student {
  private final List<Double> grades = new ArrayList<>(10);
  private final String name;
  // Constructor, getters & setters omitted. 
}

// ..
Student student = // ...
for (int i=0; i<10; i++) {
    System.out.println("Please enter the "+(i+1)+"th grade:");
    student.getGrades().add(scanner.nextDouble());
}
// ..
Student student = // ...
student.getGrades().forEach(System.out::println);

Note that is not the optimal way to do it. You can search the https://codereview.stackexchange.com/ community for "student grade java" to find a lot of review on similar questions.

Upvotes: 2

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