我怎样才能得到从另一个类返回的整数？

Question

I have a project in a computer math course where we need to take input for 3 coefficients (ax^2 + bx + c) and use the quadratic formula to calculate the zeroes. it wouldn't be super hard for us, but we have to split the work into different resource classes and a driver class.

outline: https://imgur.com/a/0Mn3m

so far this is what I have so far

import java.util.Scanner;

public class coEff
{
    public int coEff()
    {

        int a, b, c;
        double root1, root2, root3, d;

        Scanner s = new Scanner(System.in);

        System.out.print("Enter the A coefficient");
        a = s.nextInt();

        System.out.print("Enter the B coefficient");
        b = s.nextInt();

        System.out.print("Enter the C coefficient");
        c = s.nextInt();

        return coEff();

    }

}

second class:

import java.util.Scanner;

public class calcZeroes
{
    public int calcZeroes()
    {
        coEff coEff = new coEff();
        coEff.coEff();

        int a, b, c;
        double root1, root2, root3, d;

        return calcZeroes();
    }
}

I have the code to calculate the formula, but it doesn't work because the coefficients aren't initialized. any help would be appreciated :)

Answer 1

You're returning your classname at the end of each class. It's just going to be recursively calling your class. (Might even give an error, i've not tried it before). You should only return an int value in your case. For example

`int something = 0;
 return something;`

Answer 2

I assume you are new to java because you whole class structure is out of order. for starters as Bami suggested you are returning class name. In java the concept of 'polymorphism' describes a language's ability to process objects of various types and classes through a single, uniform interface. So you can make coEff class and do the calculation there and take the user input in driver class. you can pass the variables from driver class to coEff method as parameter.

  import java.util.Scanner;

  public class coEff{

  public int coEff(int a, int b, int c){
  int result;

  //do the calculation here.

  return result;
  }
}

In your driver class you take the input and use the coEff object to pass those input as parameter for you coEff method.

 import java.util.*;

 public class Driver{

 public static void main(String [] args){
  int a,b,c;
  Scanner input = new Scanner(System.in);

  System.out.println("Enter co-efficient A:\n");
  a = input.nextInt();

  System.out.println("Enter co-efficient B:\n");
  b = input.nextInt();

  System.out.println("Enter co-efficient C:\n");
  c = input.nextInt();

  coEff coeff = new coEff();

  System.out.println(coEff.coEff(a,b,c));
 }
 }

As a side note: don't use the same name for a class and the method unless it's a constructer.

EDIT: if you are required to take the input in a separate class, you can still use the same concept, instead of taking the input in driver just take it in a different class and call the coEff method and print the result in driver.