dis

package com.company;
import java.util.Scanner;
import java.lang.Math;

public class Main {

    public static double inputCoefficientA(){
        Scanner scan = new Scanner(System.in);
        double coefficient = 0;
        boolean isIncorrect;
        do {
            isIncorrect = false;
            try {
                coefficient = Double.parseDouble(scan.nextLine());
            }catch (Exception e){
                System.out.println("Enter the number!");
                isIncorrect = true;
            }

            if (!isIncorrect && coefficient == 0){
                isIncorrect = true;
                System.out.println("The equation is not quadratic. Repeat enter!.");
            }
        }while (isIncorrect);
        return coefficient;
    }

    public static double inputCoefficients(){
        Scanner scan = new Scanner(System.in);
        double coefficient = 0;
        boolean isIncorrect;
        do {
            isIncorrect = false;
            try {
                coefficient = Double.parseDouble(scan.nextLine());
            }catch (Exception e){
                System.out.println("Enter the number!");
                isIncorrect = true;
            }
        }while (isIncorrect);
        return coefficient;
    }

    public static double calculateDiscriminant(double a, double b, double c){
        return b * b - 4 * a * c;
    }

    public static void chooseDecision(double discriminant, double a, double b){
        if (discriminant >= 0){
            calculateRoots(a, b, discriminant);
        } else {
            System.out.println("The equation has no roots");
        }
    }

    public static void calculateRoots(double a, double b, double discriminant){
        double x1 = (-b + Math.sqrt(discriminant)) / (2 * a);
        double x2 = (-b - Math.sqrt(discriminant)) / (2 * a);
        printRoots(x1, x2);
    }

    public static void printRoots(double x1, double x2){
        if (x1 == x2){
            System.out.println("The root of this equation is " + x1);
        }else {
            System.out.println("the roots of this equation are " + x1 + " and " + x2);
        }
    }

    public static void main(String[] args) {
        System.out.println("Enter coefficient a");
        double a = inputCoefficientA();
        System.out.println("Enter coefficient b");
        double b = inputCoefficients();
        System.out.println("Enter coefficient c");
        double c = inputCoefficients();

        double discriminant = calculateDiscriminant(a, b, c);
        chooseDecision(discriminant, a, b);
    }
}