Question

Implement a class named Complex that represents immutable complex numbers.

• Your class needs two private final fields of type double to store the real and imaginary parts.
• Try to use constructor chaining to implement 2 of the 3 required constructors.
• If you cannot complete one or more of the methods, at least make sure that it returns some value of the correct type; this will allow the tester to run, and it will make it much easier to evaluate your code. For example, if you are having difficulty with toString then make sure that the method returns some String (such as the empty string "").

Code Given:

import java.util.Arrays;
import java.util.List;

/**
* A class that represents immutable complex numbers.
*
* @author EECS2030 Fall 2019
*
*/
public final class Complex {

  
  
   /**
   * Initializes this complex number to <code>0 + 0i</code>.
   *
   */
   public Complex() {
      
   }

   /**
   * Initializes this complex number so that it has the same real and
   * imaginary parts as another complex number.
   */
   public Complex(Complex other) {
      
   }

   /**
   * Initializes this complex number so that it has the given real
   * and imaginary components.
   */
   public Complex(double re, double im) {
      
   }

   /**
   * A static factory method that returns a new complex number whose real part
   * is equal to re and whose imaginary part is equal to 0.0
   */
   public static Complex real(double re) {
      
       return null;
   }

   /**
   * A static factory method that returns a new complex number whose real part
   * is equal to 0.0 and whose imaginary part is equal to im
   */
   public static Complex imag(double im) {
      
       return null;
   }

   /**
   * Get the real part of the complex number.
   */
   public double re() {
      
       return 0.0;
   }

   /**
   * Get the imaginary part of the complex number.
   */
   public double im() {
      
       return 0.0;
   }

   /**
   * Add this complex number and another complex number to obtain a new
   * complex number. Neither this complex number nor c is changed by
   * this method.
   */
   public Complex add(Complex c) {
      
       return null;
   }

   /**
   * Multiply this complex number with another complex number to obtain a new
   * complex number. Neither this complex number nor c is changed by
   * this method.
   */
   public Complex multiply(Complex c) {
      
       return null;
   }

   /**
   * Compute the magnitude of this complex number.
   */
   public double mag() {
      
       return 0.0;
   }

   /**
   * Return a hash code for this complex number.
   */
   @Override
   public int hashCode() {
      
       return 0;
   }

   /**
   * Compares this complex number with the specified object. The result is
   * <code>true</code> if and only if the argument is a <code>Complex</code>
   * number with the same real and imaginary parts as this complex number.
   */
   @Override
   public boolean equals(Object obj) {
      
       return true;
   }

   /**
   * Returns a string representation of this complex number.
   */
   @Override
   public String toString() {
      
       return "";
   }

   /**
   * Returns a complex number holding the value represented by the given
   * string.
   */
   public static Complex valueOf(String s) {
       Complex result = null;
       String t = s.trim();
       List<String> parts = Arrays.asList(t.split("\\s+"));
      
       // split splits the string s by looking for spaces in s.
       // If s is a string that might be interpreted as a complex number
       // then parts will be a list having 3 elements. The first
       // element will be a real number, the second element will be
       // a plus or minus sign, and the third element will be a real
       // number followed immediately by an i.
       //
       // To complete the implementation of this method you need
       // to do the following:
       //
       // -check if parts has 3 elements
       // -check if the second element of parts is "+" or "-"
       // -check if the third element of parts ends with an "i"
       // -if any of the 3 checks are false then s isn't a complex number
       // and you should throw an exception
       // -if all of the 3 checks are true then s might a complex number
       // -try to convert the first element of parts to a double value
       // (use Double.valueOf); this might fail in which case s isn't
       // a complex number
       // -remove the 'i' from the third element of parts and try
       // to convert the resulting string to a double value
   // (use Double.valueOf); this might fail in which case s isn't
       // a complex number
       // -you now have real and imaginary parts of the complex number
       // but you still have to account for the "+" or "-" which
       // is stored as the second element of parts
       // -once you account for the sign, you can return the correct
       // complex number
      
      
      
       return result;
   }
}

Answer 1

Done all the method except ValueOf, PLEASE COMMENT if there is any concern.

import java.util.Arrays;

import java.util.List;

/**

* A class that represents immutable complex numbers.

*

* @author EECS2030 Fall 2019

*

*/

public final class Complex {

  

private double real;

private double imaginary;

  

   /**

   * Initializes this complex number to <code>0 + 0i</code>.

   *

   */

   public Complex() {

real = 0;

   imaginary = 0;

   }

   /**

   * Initializes this complex number so that it has the same real and

   * imaginary parts as another complex number.

   */

   public Complex(Complex other) {

real = other.real;

   imaginary = other.imaginary;

   }

   /**

   * Initializes this complex number so that it has the given real

   * and imaginary components.

   */

   public Complex(double re, double im) {

real = re;

   imaginary = im;

   }

   /**

   * A static factory method that returns a new complex number whose real part

   * is equal to re and whose imaginary part is equal to 0.0

   */

   public static Complex real(double re) {

  

   return new Complex(re,0);

   }

   /**

   * A static factory method that returns a new complex number whose real part

   * is equal to 0.0 and whose imaginary part is equal to im

   */

   public static Complex imag(double im) {

  

   return new Complex(0,im);

   }

   /**

   * Get the real part of the complex number.

   */

   public double re() {

  

   return real;

   }

   /**

   * Get the imaginary part of the complex number.

   */

   public double im() {

  

   return imaginary;

   }

   /**

   * Add this complex number and another complex number to obtain a new

   * complex number. Neither this complex number nor c is changed by

   * this method.

   */

   public Complex add(Complex c) {

  

double r = this.real + c.real;

double im = this.imaginary + c.imaginary;

return new Complex(r,im);

   }

   /**

   * Multiply this complex number with another complex number to obtain a new

   * complex number. Neither this complex number nor c is changed by

   * this method.

   */

   public Complex multiply(Complex c) {

double r = (this.real * c.real - this.imaginary * c.imaginary);

double im = (this.real * c.imaginary + this.imaginary * c.real) ;

return new Complex(r,im);

   }

   /**

   * Compute the magnitude of this complex number.

   */

   public double mag() {

  

   return Math.sqrt(real*real + imaginary*imaginary);

   }

   @Override

public int hashCode() {

final int prime = 31;

int result = 1;

long temp;

temp = Double.doubleToLongBits(imaginary);

result = prime * result + (int) (temp ^ (temp >>> 32));

temp = Double.doubleToLongBits(real);

result = prime * result + (int) (temp ^ (temp >>> 32));

return result;

}

   @Override

public boolean equals(Object obj) {

if (this == obj)

return true;

if (obj == null)

return false;

if (getClass() != obj.getClass())

return false;

Complex other = (Complex) obj;

if (Double.doubleToLongBits(imaginary) != Double.doubleToLongBits(other.imaginary))

return false;

if (Double.doubleToLongBits(real) != Double.doubleToLongBits(other.real))

return false;

return true;

}

   /**

   * Returns a string representation of this complex number.

   */

   @Override

   public String toString() {

  

if (imaginary == 0) return real + "";

   if (real == 0) return imaginary + "i";

   if (imaginary < 0) return real + " - " + (-imaginary) + "i";

   return real + " + " + imaginary + "i";

   }

   /**

   * Returns a complex number holding the value represented by the given

   * string.

   */

   public static Complex valueOf(String s) {

   Complex result = null;

   String t = s.trim();

   List<String> parts = Arrays.asList(t.split("\\s+"));

  

   // split splits the string s by looking for spaces in s.

   // If s is a string that might be interpreted as a complex number

   // then parts will be a list having 3 elements. The first

   // element will be a real number, the second element will be

   // a plus or minus sign, and the third element will be a real

   // number followed immediately by an i.

   //

   // To complete the implementation of this method you need

   // to do the following:

   //

   // -check if parts has 3 elements

   // -check if the second element of parts is "+" or "-"

   // -check if the third element of parts ends with an "i"

   // -if any of the 3 checks are false then s isn't a complex number

   // and you should throw an exception

   // -if all of the 3 checks are true then s might a complex number

   // -try to convert the first element of parts to a double value

   // (use Double.valueOf); this might fail in which case s isn't

   // a complex number

   // -remove the 'i' from the third element of parts and try

   // to convert the resulting string to a double value

   // (use Double.valueOf); this might fail in which case s isn't

   // a complex number

   // -you now have real and imaginary parts of the complex number

   // but you still have to account for the "+" or "-" which

   // is stored as the second element of parts

   // -once you account for the sign, you can return the correct

   // complex number

  

  

  

   return result;

   }

}

==============================

SEE CODE

Done all the method except ValueOf, PLEASE COMMENT if there is any concern.