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ch 13 Ex: 17
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‎src/ch_13/exercise13_16/Exercise13_16.java

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package ch_13.exercise13_16;
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import java.util.Map;
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import java.util.Set;
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/**
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* 13.16 (Create a rational-number calculator) Write a program similar to Listing 7.9,
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* Calculator.java. Instead of using integers, use rationals, as shown in Figure 13.10a.
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public class Exercise13_16 {
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public static void main(String[] args) {
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System.out.println("See RationalNumCalculator.java....");
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System.out.println("javac RationalNumCalculator.java");
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System.out.print("Usage: java RationalNumCalculator \"11/453 +-*/ 7/44\" ");
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System.out.print(" or: java RationalNumCalculator \"112 +-*/ 9/17\" ");
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}
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}

‎src/ch_13/exercise13_16/RationalNumCalculator.java

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* Section 10.10.3, Replacing and Splitting Strings, to retrieve the numerator string and
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* denominator string, and convert strings into integers using the Integer.parseInt
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* method.
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*
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* Usage: java RationalNumCalculator 11/453 * 7/44
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* <p>
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* Usage: java RationalNumCalculator "1/5 * 7/8"
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*/
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public class RationalNumCalculator {
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public static void main(String[] args) {
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if (args.length != 3) {
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System.out.println(
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"Usage: java RNumCalculator operand1 operator operand2");
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"Usage: java RNumCalculator \"operand1 operator operand2\" ");
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System.exit(0);
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}
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if (args[0].contains("/") || args[2].contains("/")) {

‎src/ch_13/exercise13_17/Complex.java

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package ch_13.exercise13_17;
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/**
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* 13.17 (Math: The Complex class) A complex number is a number in the form a + bi,
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* -where a and b are real numbers and i is SQRT(-1). The numbers a and b are known
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* as the real part and imaginary part of the complex number, respectively. You can
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* perform addition, subtraction, multiplication, and division for complex numbers
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* using the following formulas:
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* a + bi + c + di = (a + c) + (b + d)i
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* a + bi - (c + di) = (a - c) + (b - d)i
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* (a + bi)*(c + di) = (ac - bd) + (bc + ad)i
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* (a + bi)/(c + di) = (ac + bd)/(c2 + d2) + (bc - ad)i/(c2 + d2)
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* <p>
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* You can also obtain the absolute value for a complex number using the following
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* formula:
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* |a + bi| = SQRT(a2 + b2)
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* (A complex number can be interpreted as a point on a plane by identifying the (a,b)
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* values as the coordinates of the point. The absolute value of the complex number
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* corresponds to the distance of the point to the origin, as shown in Figure 13.10b.)
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* <p>
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* Design a class named Complex for representing complex numbers and the
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* methods add, subtract, multiply, divide, and abs for performing complex number operations,
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* and override toString method for returning a string representation for a complex number.
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* The toString method returns (a + bi) as a string. If b is 0, it simply returns a.
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* Your Complex class should also implement the Cloneable interface.
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* <p>
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* Provide three constructors Complex(a, b), Complex(a), and Complex().
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* Complex() creates a Complex object for number 0 and Complex(a) creates a Complex object with 0 for b.
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* Also provide the getRealPart() and getImaginaryPart() methods for returning the real and imaginary part
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* of the complex number, respectively.
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*/
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public class Complex extends Number implements Cloneable {
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private double a;
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private double b;
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private static double i = Math.sqrt(-1);
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public Complex() {
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this(0);
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}
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public Complex(double a) {
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this(a, 0);
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}
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public Complex(double a, double b) {
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this.a = a;
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this.b = b;
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}
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/**
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* Example addition: (a + bi) + (c + di) = (a + c) + (b + d)i
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*
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* @param complex Complex number to add
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* @return the addition result
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*/
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public double add(Complex complex) {
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return (this.a + complex.a) + (this.b + complex.b) * i;
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}
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/**
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* Subtract example:
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* a + bi - (c + di) = (a - c) + (b - d)i
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*
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* @param complex
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* @return
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*/
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public double subtract(Complex complex) {
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return (this.a - complex.a) + (this.b - complex.b) * i;
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}
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/**
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* (a + bi)*(c + di) = (ac - bd) + (bc + ad)i
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*
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* @param complex
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* @return
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*/
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public double multiply(Complex complex) {
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return (this.a * complex.a - this.b * complex.b) + ((this.b * complex.a + this.a * complex.b) * i);
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}
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/**
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* (a + bi)/(c + di) = (ac + bd)/(c2 + d2) + (bc - ad)i/(c2 + d2)
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*
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* @param complex
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* @return
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*/
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public double divide(Complex complex) {
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return (this.a * complex.a + this.b * complex.b) / (Math.pow(complex.a, 2) + Math.pow(complex.b, 2)) + ((this.b * complex.a - this.a * complex.b) * i) / (Math.pow(complex.a, 2) + Math.pow(complex.b, 2));
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}
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public double abs(Complex complex) {
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return Math.sqrt(Math.pow(this.a, 2) + Math.pow(this.b, 2));
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}
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public double getRealPart() {
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return a;
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}
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public double getImaginaryPart() {
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return b * i;
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}
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@Override
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public Complex clone() throws CloneNotSupportedException {
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return (Complex) super.clone();
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}
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@Override
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public int intValue() {
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return (int) Math.round(a + b * i);
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}
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@Override
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public long longValue() {
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return Math.round(a + b * i);
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}
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@Override
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public float floatValue() {
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return (float) (a + b * i);
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}
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@Override
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public double doubleValue() {
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return a + b * i;
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}
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}

‎src/ch_13/Exercise13_17.java renamed to ‎src/ch_13/exercise13_17/Exercise13_17.java

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package ch_13;
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package ch_13.exercise13_17;
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/**
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* 13.17 (Math: The Complex class) A complex number is a number in the form a + bi,
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* where a and b are real numbers and i is 2-1. The numbers a and b are known
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* where a and b are real numbers and i is SQRT(-1). The numbers a and b are known
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* as the real part and imaginary part of the complex number, respectively. You can
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* perform addition, subtraction, multiplication, and division for complex numbers
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* using the following formulas:
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* a + bi + c + di = (a + c) + (b + d)i
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* a + bi - (c + di) = (a - c) + (b - d)i
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* (a + bi)*(c + di) = (ac - bd) + (bc + ad)i
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* (a + bi)/(c + di) = (ac + bd)/(c2 + d2) + (bc - ad)i/(c2 + d2)
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* a + bi + c + di = (a + c) + (b + d)i
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* a + bi - (c + di) = (a - c) + (b - d)i
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* (a + bi)*(c + di) = (ac - bd) + (bc + ad)i
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* (a + bi)/(c + di) = (ac + bd)/(c2 + d2) + (bc - ad)i/(c2 + d2)
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* <p>
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* You can also obtain the absolute value for a complex number using the following
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* formula:
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* a + bi = 2a2 + b2
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* a + bi = 2a2 + b2
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* (A complex number can be interpreted as a point on a plane by identifying the (a,b)
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* values as the coordinates of the point. The absolute value of the complex number
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* corresponds to the distance of the point to the origin, as shown in Figure 13.10b.)
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* Provide three constructors Complex(a, b), Complex(a), and Complex().
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* Complex() creates a Complex object for number 0 and Complex(a) creates a Complex object with 0 for b.
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* Also provide the getRealPart() and getImaginaryPart() methods for returning the real and imaginary part
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* of the complex number, respectively. Write a test program that prompts the user to enter two complex numbers and
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* of the complex number, respectively.
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* <p>
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* <p>
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* Write a test program that prompts the user to enter two complex numbers and
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* displays the result of their addition, subtraction, multiplication, division, and absolute value.
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*
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* <p>
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* Here is a sample run:
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* Enter the first complex number: 3.5 5.5
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* Enter the second complex number: -3.5 1
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* |(3.5 + 5.5i)| = 6.519202405202649
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*/
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public class Exercise13_17 {
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public static void main(String[] args) {
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System.out.println("See -> exercise13_17.Complex.class");
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}
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}

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