Question

Create a new folder called CSCI130_A3_yourname. Create all of the files indicated below within this folder.

For this assignment you will be creating a total of 2 classes that meet the definitions below. This assignment will allow the user to enter in the coefficients for a polynomial function of degree 2. The user will then be asked to enter a number. The program will use that number as an argument to the function, and will print the corresponding function value.

Keep in mind that a second degree polynomial function in general form looks like:

    f(x) = ax² + bx + c (here 'a' is the coefficient of the quadratic term, 'b' is the coefficient of the linear term, and 'c' is the constant)

Refer to the image at the bottom of this page to get a better understanding of the logic flow.

CLASSES:

1. Polynomial - this class should be in a file named Polynomial.java
2. Assignment3 - this class should be in a file named Assignment3.java

CLASS DEFINITIONS:

class Polynomial

Data (instance variables) - all have private access

• double quadraticCoefficient (this is the coefficient of the quadratic term of the polynomial)
• double linearCoefficient (this is the coefficient of the linear term of the polynomial)
• double constant (this is the constant of the polynomial)

Methods (behaviors) - all have public access

constructor:

• Arguments:
  • None
• Return
  • None
• Behavior
  • Calls Polynomial's constructPolynomial instance method

constructPolynomial:

• Arguments:
  • None
• Return
  • None
• Behavior
  • Allows user to enter the necessary coefficients and the constant term for the polynomial, and sets the attributes accordingly

functionValue:

• Arguments:
  • double arg
• Return
  • double
• Behavior
  • Calculates and returns the function value using the argument arg (for example, if the user entered the polynomial 3x² + 2x + 7, then functionValue(3) would return 40)

displaySelf:

• Arguments:
  • None
• Return
  • None
• Behavior
  • Neatly displays the polynomial entered by the user

class Assignment3

Methods

public static void main(String[] args):

• Arguments:
  • String[] args
• Return:
  • None
• Behavior (see image below for clarification):
  • The polynomial is constructed
  • The user is asked for the argument to the function
  • The polynomial is displayed
  • The function value (based on the argument and Polynomial entered) is displayed

After writing the code, do the following:

• Compile and execute the code. Fix any errors that occur at either stage. Continue this process until the program runs correctly.
  
• Document the code by putting your name, the date, assignment number, and instructor in comments at the top of the Driver.java file.
  
• Submit your assignment be either:
  • uploading both files within the CSCI130_A3_yourname folder to Canvas
    OR
  • zipping the entire CSCI130_A3_yourname folder and uploading the zipped file to Canvas

Answer 1

Code in Java:

class Polynomial
{
   private double quadraticCoefficient;
   private double linearCoefficient;
   private double constant;
  
   Polynomial()
   {
       constructPolynomial(); //constructor calls this instance method
   }
  
   public void constructPolynomial()
   {
       Scanner sc = new Scanner(System.in); //to input values from user
       System.out.println("Enter quadraticCoefficient: ");
       quadraticCoefficient = sc.nextDouble();
      
       System.out.println("Enter linearCoefficient: ");
       linearCoefficient = sc.nextDouble();
      
       System.out.println("Enter constant: ");
       constant = sc.nextDouble();
   }
  
   public double functionValue(double arg)
   {
       double v1 = quadraticCoefficient*quadraticCoefficient*arg;
      
       return((quadraticCoefficient*quadraticCoefficient*arg) + (linearCoefficient*arg) + (constant));
   }
  
   public void displaySelf()
   {
       System.out.println(quadraticCoefficient + "x2" + " + " + linearCoefficient + "x + " + constant);
   }
}

public class Assignment3{
   public static void main(String[] args)
   {
       Polynomial poly = new Polynomial();
       poly.displaySelf();
       System.out.println(poly.functionValue(3));

//since not mentioned in question, function value - 3 is fed hereitself. However, if required to be taken from user, the same //Scanner function used earlier for taking the coefficients can be used to take this value here itself.
   }
}