Question

Java Programming Question.

I am writing a code to calculate the roots of the quadratic equation based on the values of the coefficients A, B, and C. I am supposed to enter 5 values for each coefficient, and the output should be five different answers (see example) using a for loop and if else statements. However, when I run my code, I am only able to enter one value for each coefficient and the output is one answer repeated five times. How do I fix this? My code is below.

For example enter the following for A, B, and C:

A B C

5 2 2

0 0 4

0 3 6

1 2 1

2 5 2

import java.util.Scanner;
public class Quatratic
{
public static void main (String [] args)
{
int i, CoeffA, CoeffB, CoeffC;
double Disc, X1, X2;
  
Scanner sc = new Scanner (System.in);
  
//Read in coefficients A, B, and C.
System.out.println ("Enter the five coefficients for each A, B, and C");
  
CoeffA = sc.nextInt();
CoeffB = sc.nextInt();
CoeffC = sc.nextInt();
  
//Calculate discriminant.
Disc = (CoeffB * CoeffB) - (4 * CoeffA * CoeffC);
  
//For loop.
for (i = 0; i < 5; i++)
{
// If disciminant and coefficient A are greater than zero, calculate the two roots.
if (Disc > 0 && CoeffA > 0)
{
X1 = CoeffB + Math.sqrt (Disc) / (2 * CoeffA);
X2 = CoeffB - Math.sqrt (Disc) / (2 * CoeffA);
System.out.println ("The equation has roots " + X1 + " and " + X2);
}
//If coefficient A and B are equal to zero, there are no roots.
else if (CoeffA == 0 && CoeffB == 0)
{
System.out.println ("The equation has no roots");
}
//If coefficient A is equal to zero, calculate the single root.
else if (CoeffA == 0)
{
X1 = - CoeffC / CoeffB;
System.out.println ("The equation has a single root equal to " + X1);
}
//If discriminant is less than zero, there are no real roots.
else if (Disc < 0)
{
System.out.println ("The equation has no real roots (imaginary)");
}
//If discriminant is equal to zero, calculate the two roots.
else if (Disc == 0)
{
X1 = - CoeffB / (2 * CoeffA);
System.out.println ("The equation has two roots equal to " + X1);
}
}
}
}

Answer 1

$\color{blue}\underline{Quatratic.java:}$

import java.util.Scanner;
public class Quatratic
{
    public static void main (String [] args)
    {
        int i, CoeffA, CoeffB, CoeffC;
        double Disc, X1, X2;

        Scanner sc = new Scanner (System.in);

        //Read in coefficients A, B, and C.
        System.out.println ("Enter the five coefficients for each A, B, and C");

        //For loop.
        for (i = 0; i < 5; i++)
        {
            CoeffA = sc.nextInt();
            CoeffB = sc.nextInt();
            CoeffC = sc.nextInt();

            //Calculate discriminant.
            Disc = (CoeffB * CoeffB) - (4 * CoeffA * CoeffC);
            
            // If disciminant and coefficient A are greater than zero, calculate the two roots.
            if (Disc > 0 && CoeffA > 0)
            {
                X1 = CoeffB + Math.sqrt (Disc) / (2 * CoeffA);
                X2 = CoeffB - Math.sqrt (Disc) / (2 * CoeffA);
                System.out.println ("The equation has roots " + X1 + " and " + X2);
            }
            //If coefficient A and B are equal to zero, there are no roots.
            else if (CoeffA == 0 && CoeffB == 0)
            {
                System.out.println ("The equation has no roots");
            }
            //If coefficient A is equal to zero, calculate the single root.
            else if (CoeffA == 0)
            {
                X1 = - CoeffC / CoeffB;
                System.out.println ("The equation has a single root equal to " + X1);
            }
            //If discriminant is less than zero, there are no real roots.
            else if (Disc < 0)
            {
                System.out.println ("The equation has no real roots (imaginary)");
            }
            //If discriminant is equal to zero, calculate the two roots.
            else if (Disc == 0)
            {
                X1 = - CoeffB / (2 * CoeffA);
                System.out.println ("The equation has two roots equal to " + X1);
            }
        }
    }
}

$\color{red}\underline{Output:}$

?

Enter the five coefficients for each A, B, and C 5 2 2 The equation has no real roots (imaginary) The equation has no roots The equation has a single root equal to-2.0 1 2 The equation has two roots equal to -1.0 2 The equation has roots 5.75 and 4.25 Process finished with exit code 0