Assign multiple values of objects using a loop-CodePudding

The question requires us to create two objects of the Student class and have 5 variables. The variables will be assigned a value each through user input.

Is there a way to use a loop or anything else to take the user inputs from there instead of writing each variable individually using the dot operator?

public class Main {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        Student student1 = new Student();
        Student student2 = new Student();

        //Input for student 1
        student1.name = input.nextLine();
        student1.gender = input.next().charAt(0);
        student1.cgpa = input.nextDouble();
        student1.roll[0] = input.nextInt();
        student1.age = input.nextInt();

        //Input for student 2
        student2.name = input.nextLine();
        student2.gender = input.next().charAt(0);
        student2.cgpa = input.nextDouble();
        student2.roll[0] = input.nextInt();
        student2.age = input.nextInt();

    }
}

class Student {
    String name;
    char gender;
    double cgpa;
    int[] roll;
    int age;
}

CodePudding user response：

We can create a constructor for the class Student that takes in the parameters and defines them as so:

class Student {
    String name;
    char gender;
    double cgpa;
    int[] roll = new int[10];
    int age;
    public Student(String n,char g,double c,int r,int a){
      name = n;
      gender = g;
      cgpa = c;
      roll[0] = r;
      age = a;
    }
    public String toString(){
      return name;
    }
}

Note that we must give roll a specified length before assigning it any elements. Alternatively, we could use an ArrayList instead of an array for roll if we are not given the length (I used 10 as a placeholder).

As for the main method, we can now define student1 and student2 in one line each:

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        Student student1 = new Student(input.nextLine(), input.next().charAt(0), input.nextDouble(), input.nextInt(), input.nextInt());
      
        input.nextLine();
      
        Student student2 = new Student(input.nextLine(), input.next().charAt(0), input.nextDouble(), input.nextInt(), input.nextInt());

        System.out.println(student1);
        System.out.println(student2);


    }
}

Notice how between the declarations of student1 and student2 there is a input.nextLine(). This is because after we take the final parameter, an integer, for student1, the input will leave a trailing newline which will mess with the user input for student2. To fix this, we can scan the line to get rid of the whitespace.

I hope this helped! Please let me know if you need any further clarification or details :)

CodePudding user response：

List.of(student1, student2, student3, student4).forEach(student ->{
        student.name = input.nextLine();
        student.gender = input.next().charAt(0);
        student.cgpa = input.nextDouble();
        student.roll[0] = input.nextInt();
        student.age = input.nextInt();
});