Restore

Labs/Lab6/Lab6_2230026071/Question3/.classpath

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+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER">
+		<attributes>
+			<attribute name="module" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>

Labs/Lab6/Lab6_2230026071/Question3/.project

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+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>Question3</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>

Labs/Lab6/Lab6_2230026071/Question3/.settings/org.eclipse.core.resources.prefs

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+eclipse.preferences.version=1
+encoding/<project>=UTF-8

Labs/Lab6/Lab6_2230026071/Question3/src/Circle.java

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+
+public class Circle extends Shape{
+	//instance variable
+	private double radius;
+	
+	//constructor
+	public Circle(double x, double y, double radius) {
+		super(x, y);
+		this.radius = radius;
+	}
+	
+	//method
+	public double area() {
+		return Math.PI * this.radius * this.radius;
+	}
+	
+	//test
+	public static void testCircle() {
+		Circle c = new Circle(1.2, 3.4, 4.0);
+		// getX and getY are inherited from Shape.
+		// area comes from Circle itself.
+		System.out.println(c.getX() == 1.2);
+		System.out.println(c.getY() == 3.4);
+		System.out.println(c.area() == Math.PI * 16.0);
+		}
+}

Labs/Lab6/Lab6_2230026071/Question3/src/Dot.java

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+
+public class Dot extends Shape {
+	//constructor
+	public Dot(double x, double y) {
+		super(x, y);
+	}
+	
+	//method
+	public double area() {return 0.0;} //a dot has no geo-area
+	
+	//test
+	public static void testDot() {
+		Dot d = new Dot(1.2, 3.4);
+		// getX and getY are inherited from Shape.
+		// area comes from Dot itself.
+		System.out.println(d.getX() == 1.2);
+		System.out.println(d.getY() == 3.4);
+		System.out.println(d.area() == 0.0);
+		}
+}

Labs/Lab6/Lab6_2230026071/Question3/src/Shape.java

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+
+public class Shape {
+	//instance variables
+	private double x;
+	private double y;
+	
+	//constructor
+	public Shape(double x, double y) {
+		this.x = x;
+		this.y = y;
+	}
+	
+	//methods
+	public double getX() {return this.x;}
+	
+	public double getY() {return this.y;}
+	
+	public double area() {
+		System.out.println("An unknown shape has an unknown area!");
+		return -1.0;
+	}
+	
+	//test
+	public static void testShape() {
+		Shape s = new Shape(1.2, 3.4);
+		System.out.println(s.getX() == 1.2);
+		System.out.println(s.getY() == 3.4);
+		System.out.println(s.area() == -1.0); // Will print an error message too.
+		}
+
+}

Labs/Lab6/Lab6_2230026071/Question3/src/Start.java

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+
+public class Start {
+
+	public static void main(String[] args) {
+		Shape.testShape();
+		Circle.testCircle();
+		Dot.testDot();
+	}
+
+}