Add assignment-1 files

.idea/workspace.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="ChangeListManager">
-    <list default="true" id="eb83f898-ce72-4016-9e31-9b6d7a32bbb2" name="Changes" comment="" />
+    <list default="true" id="eb83f898-ce72-4016-9e31-9b6d7a32bbb2" name="Changes" comment="">
+      <change afterPath="$PROJECT_DIR$/.gitignore" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/.idea/misc.xml" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/.idea/modules.xml" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/.idea/vcs.xml" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/Assignment_1.iml" afterDir="false" />
+    </list>
     <option name="SHOW_DIALOG" value="false" />
     <option name="HIGHLIGHT_CONFLICTS" value="true" />
     <option name="HIGHLIGHT_NON_ACTIVE_CHANGELIST" value="false" />

src/CalculateArea.java

+public class CalculateArea {
+    CalculateArea() {
+        int n;
+    }
+    int cube(int n) {
+        return (int) Math.pow(n, 3);
+    }
+}

src/Car.java

+// Example of composition
+class Car {
+
+    private Engine carEngine;
+    public String name;
+    public int mileage;
+
+
+    // Initialize constructor
+    public Car(String name, int mileage, Engine carEngine) {
+        this.name = name;
+        this.mileage = mileage;
+        setCarEngine(carEngine);
+    }
+
+    public void setCarEngine(Engine carEngine) {
+        this.carEngine = carEngine;
+    }
+
+
+
+}

src/Engine.java

+public class Engine {
+    public String type;
+
+    Engine(String type) {
+        this.type = type;
+
+    }
+
+    public void startEngine() {
+        System.out.println("Engine has started.");
+    }
+
+    public void stopEngine() {
+        System.out.println("Engine has stopped");
+    }
+
+}

src/Main.java

+public class Main {
+    public static void main(String[] args) {
+
+
+//      Part 1. Implement Encapsulation.
+
+        // create object of Student
+        Student myStudent = new Student("Qadeer", 321);
+
+        // Test setter and getter methods
+        System.out.println(myStudent.getName());
+        myStudent.setName("Muhammad");
+        System.out.println(myStudent.getName());
+        System.out.println(myStudent.getRollNo());
+        myStudent.setRollNo(111);
+        System.out.println(myStudent.getRollNo());
+
+//      Part 2. Implement a Singleton class.
+
+        // Get object available.
+        SingleParent mySingleParent = SingleParent.getSingleParent();
+        mySingleParent.introduce();
+
+        // Create another object.
+        SingleParent secondSingleParent = SingleParent.getSingleParent();
+
+        // Determine if both objects are same.
+        System.out.println(mySingleParent == secondSingleParent);
+
+        // Displays object reference
+        System.out.println(mySingleParent);
+        System.out.println(secondSingleParent);
+
+//      Part 3. Section 1. Composition
+
+
+        // Create object consisting of Engine.
+        Engine engine = new Engine("car");
+
+        Car mclaren = new Car("mclaren", 321,engine);
+
+//      Part 3. Section 2. Aggregation
+
+/*        // Create object of Sphere
+        Sphere s = new Sphere(3);
+        double answer = s.surfaceArea();
+        System.out.println("The surface area is: " + answer);*/
+
+
+    }
+}

src/SingleParent.java

+public class SingleParent {
+    private static SingleParent instanceSingleParent = new SingleParent();
+    private SingleParent() {}
+
+    // getter
+    public static SingleParent getSingleParent() {
+        return instanceSingleParent;
+    }
+
+    // data method
+    public void introduce() {
+        System.out.println("I am a Singleton Class.");
+    }
+
+}

src/Sphere.java

+public class Sphere {
+
+    // entity reference
+    CalculateArea cl;
+    double pi = 3.14;
+    int radius;
+
+    // constructor
+    Sphere(int radius) {
+        this.radius = radius;
+    }
+    double surfaceArea() {
+        cl = new CalculateArea();
+        int myCube = cl.cube(radius);
+        return 4.0 * pi * myCube;
+    }
+}

src/Student.java

+// Part 1 of Assignment 1
+public class Student {
+
+    // Declare private data members.
+    private String name;
+    private int rollNo;
+
+    // Create constructor
+    Student(String name, int rollNo) {
+        setName(name);
+        setRollNo(rollNo);
+
+    }
+
+    // Setter and Getters
+    public String getName() {
+        return name;
+    }
+    public void setName(String name) {
+        this.name = name;
+    }
+    public int getRollNo() {
+        return rollNo;
+    }
+    public void setRollNo(int rollNo) {
+        this.rollNo = rollNo;
+    }
+
+
+}