Tutorial 5

T5Q1/src/ClassA.java

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+public class ClassA {
+    public void print(int x, String y) {
+        System.out.println(x + " " + y);
+    }
+}

T5Q1/src/ClassB.java

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+public class ClassB extends ClassA {
+    public void print(int x) {
+        System.out.println(x);
+    }
+}

T5Q1/src/ClassC.java

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+public class ClassC extends ClassA {
+    public void print(String x, String y) {
+        System.out.println(x + " " + y);
+    }
+}

T5Q1/src/ClassD.java

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+public class ClassD extends ClassC {
+    public void print(String a, String b) {
+        System.out.println(a + " " + b);
+    }
+}

T5Q1/src/ClassE.java

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+public class ClassE extends ClassC {
+    public void print(String x) {
+        System.out.println(x);
+    }
+}

T5Q1/src/ClassF.java

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+public class ClassF extends ClassE {
+    public void print(int x) {
+        System.out.println(x);
+    }
+}

T5Q1/src/ClassG.java

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+public class ClassG extends ClassF {
+    public void print(String x) {
+        System.out.println(x);
+    }
+}

T5Q1/src/Main.java

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+public class Main {
+    public static void main(String[] args) {
+        ClassF z = new ClassF();
+
+        z.print(9);
+        z.print(2, "Cx2002");
+        z.print("Object");
+        z.print("OODP", "Java");
+//        z.print("OODP", 2002); // Compilation error
+    }
+}

T5Q2-A-Sol1/src/ClassA.java

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+public class ClassA {
+    public void print(int x, String y) {
+        System.out.println(x + " " + y);
+    }
+}

T5Q2-A-Sol1/src/ClassB.java

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+public class ClassB extends ClassA {
+    public void print(int x) {
+        System.out.println(x);
+    }
+}

T5Q2-A-Sol1/src/ClassC.java

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+public abstract class ClassC extends ClassA {
+    public abstract void print(String x, String y);
+}

T5Q2-A-Sol1/src/ClassD.java

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+public class ClassD extends ClassC {
+    public void print(String a, String b) {
+        System.out.println(a + " " + b);
+    }
+}

T5Q2-A-Sol1/src/ClassE.java

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+public class ClassE extends ClassC {
+    public void print(String x) {
+        System.out.println(x);
+    }
+    public void print(String x, String y) {
+        System.out.println(x + " " + y);
+    }
+}

T5Q2-A-Sol1/src/ClassF.java

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+public class ClassF extends ClassE {
+    public void print(int x) {
+        System.out.println(x);
+    }
+}

T5Q2-A-Sol1/src/ClassG.java

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+public class ClassG extends ClassF {
+    public void print(String x) {
+        System.out.println(x);
+    }
+}

T5Q2-A-Sol1/src/Main.java

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+public class Main {
+    public static void main(String[] args) {
+        ClassF z = new ClassF();
+    }
+}

T5Q2-A-Sol2/src/ClassA.java

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+public class ClassA {
+    public void print(int x, String y) {
+        System.out.println(x + " " + y);
+    }
+}

T5Q2-A-Sol2/src/ClassB.java

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+public class ClassB extends ClassA {
+    public void print(int x) {
+        System.out.println(x);
+    }
+}

T5Q2-A-Sol2/src/ClassC.java

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+public abstract class ClassC extends ClassA {
+    public abstract void print(String x, String y);
+}

T5Q2-A-Sol2/src/ClassD.java

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+public class ClassD extends ClassC {
+    public void print(String a, String b) {
+        System.out.println(a + " " + b);
+    }
+}

T5Q2-A-Sol2/src/ClassE.java

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+public abstract class ClassE extends ClassC {
+    public void print(String x) {
+        System.out.println(x);
+    }
+    public abstract void print(String x, String y);
+}

T5Q2-A-Sol2/src/ClassF.java

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+public class ClassF extends ClassE {
+    public void print(int x) {
+        System.out.println(x);
+    }
+    public void print(String x, String y) {
+        System.out.println(x + " " + y);
+    }
+}

T5Q2-A-Sol2/src/ClassG.java

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+public class ClassG extends ClassF {
+    public void print(String x) {
+        System.out.println(x);
+    }
+    public void print(String x, String y) {
+        System.out.println(x + " " + y);
+    }
+}

T5Q2-A-Sol2/src/Main.java

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+public class Main {
+    public static void main(String[] args) {
+
+    }
+}

T5Q2-A/src/ClassA.java

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+public class ClassA {
+    public void print(int x, String y) {
+        System.out.println(x + " " + y);
+    }
+}

T5Q2-A/src/ClassB.java

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+public class ClassB extends ClassA {
+    public void print(int x) {
+        System.out.println(x);
+    }
+}

T5Q2-A/src/ClassC.java

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+public abstract class ClassC extends ClassA {
+    public abstract void print(String x, String y);
+}

T5Q2-A/src/ClassD.java

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+public class ClassD extends ClassC {
+    public void print(String a, String b) {
+        System.out.println(a + " " + b);
+    }
+}

T5Q2-A/src/ClassE.java

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+public class ClassE extends ClassC {
+    public void print(String x) {
+        System.out.println(x);
+    }
+}

T5Q2-A/src/ClassF.java

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+public class ClassF extends ClassE {
+    public void print(int x) {
+        System.out.println(x);
+    }
+}

T5Q2-A/src/ClassG.java

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+public class ClassG extends ClassF {
+    public void print(String x) {
+        System.out.println(x);
+    }
+}

T5Q2-A/src/Main.java

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+public class Main {
+    public static void main(String[] args) {
+        ClassF z = new ClassF();
+    }
+}

T5Q2-B-FromSol1/src/ClassA.java

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+public class ClassA {
+    public void print(int x, String y) {
+        System.out.println(x + " " + y);
+    }
+}

T5Q2-B-FromSol1/src/ClassB.java

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+public class ClassB extends ClassA {
+    public void print(int x) {
+        System.out.println(x);
+    }
+}

T5Q2-B-FromSol1/src/ClassC.java

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+public abstract class ClassC extends ClassA {
+    public abstract void print(String x, String y);
+}

T5Q2-B-FromSol1/src/ClassD.java

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+public class ClassD extends ClassC {
+    public void print(String a, String b) {
+        System.out.println(a + " " + b);
+    }
+}

T5Q2-B-FromSol1/src/ClassE.java

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+public class ClassE extends ClassC {
+    public void print(String x) {
+        System.out.println(x);
+    }
+    public void print(String x, String y) {
+        System.out.println(x + " " + y);
+    }
+}

T5Q2-B-FromSol1/src/ClassF.java

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+public class ClassF extends ClassE {
+    public void print(int x) {
+        System.out.println(x);
+    }
+}

T5Q2-B-FromSol1/src/ClassG.java

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+public class ClassG extends ClassF {
+    public void print(String x) {
+        System.out.println(x);
+    }
+}

T5Q2-B-FromSol1/src/Main.java

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+public class Main {
+    public static void main(String[] args) {
+        // I - Works
+//        ClassC c = new ClassD();
+//        c.print("hello", "there");
+
+        // II - Does not compile because class C is abstract
+//        ClassA a = new ClassC();
+//        a.print(1, "there");
+
+        // III - Doesn't work - Class A does not have print(string, string) method
+//        ClassA a = new ClassF();
+//        a.print("hello", "there");
+    }
+}

T5Q2-B-FromSol2/src/ClassA.java

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+public class ClassA {
+    public void print(int x, String y) {
+        System.out.println(x + " " + y);
+    }
+}

T5Q2-B-FromSol2/src/ClassB.java

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+public class ClassB extends ClassA {
+    public void print(int x) {
+        System.out.println(x);
+    }
+}

T5Q2-B-FromSol2/src/ClassC.java

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+public abstract class ClassC extends ClassA {
+    public abstract void print(String x, String y);
+}

T5Q2-B-FromSol2/src/ClassD.java

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+public class ClassD extends ClassC {
+    public void print(String a, String b) {
+        System.out.println(a + " " + b);
+    }
+}

T5Q2-B-FromSol2/src/ClassE.java

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+public abstract class ClassE extends ClassC {
+    public void print(String x) {
+        System.out.println(x);
+    }
+    public abstract void print(String x, String y);
+}

T5Q2-B-FromSol2/src/ClassF.java

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+public class ClassF extends ClassE {
+    public void print(int x) {
+        System.out.println(x);
+    }
+    public void print(String x, String y) {
+        System.out.println(x + " " + y);
+    }
+}

T5Q2-B-FromSol2/src/ClassG.java

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+public class ClassG extends ClassF {
+    public void print(String x) {
+        System.out.println(x);
+    }
+    public void print(String x, String y) {
+        System.out.println(x + " " + y);
+    }
+}

T5Q2-B-FromSol2/src/Main.java

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+public class Main {
+    public static void main(String[] args) {
+        // I - Works
+        ClassC c = new ClassD();
+        c.print("hello", "there");
+
+        // II - Does not compile because class C is abstract
+//        ClassA a = new ClassC();
+//        a.print(1, "there")
+
+        // III - Works
+        ClassF a = new ClassF();
+        a.print("hello", "there");
+    }
+}

T5Q2-C/src/ClassA.java

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+public class ClassA {
+    public void print(int x, String y) {
+        System.out.println(x + " " + y);
+    }
+}

T5Q2-C/src/ClassB.java

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+public class ClassB extends ClassA {
+    public void print(int x) {
+        System.out.println(x);
+    }
+}

T5Q2-C/src/ClassC.java

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+public class ClassC extends ClassA {
+    public void print(String x, String y) {
+        System.out.println(x + " " + y);
+    }
+}

T5Q2-C/src/ClassD.java

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+public class ClassD extends ClassC {
+    public void print(String a, String b) {
+        System.out.println(a + " " + b);
+    }
+}

T5Q2-C/src/ClassE.java

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+public class ClassE extends ClassC {
+    public void print(String x) {
+        System.out.println(x);
+    }
+}

T5Q2-C/src/ClassF.java

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+public class ClassF extends ClassE {
+    public void print(int x) {
+        System.out.println(x);
+    }
+}

T5Q2-C/src/ClassG.java

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+public class ClassG extends ClassF {
+    public void print(String x) {
+        System.out.println(x);
+    }
+}

T5Q2-C/src/Main.java

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+public class Main {
+    public static void main(String[] args) {
+        // I - Doesn't work because downcast needs to be explicitly declared
+//        ClassC c = new ClassD();
+//        ClassE e = c;
+
+        // II - Can´t upcast because they are from different family branches
+//        ClassB b = new ClassE();
+//        b.print("hello");
+
+        // III
+//        ClassA a = new ClassF(); // Ok
+//        a.print(12, "there"); // Ok
+//        a.print(88); // Compilation error
+
+        // IV -
+//        ClassA a = new ClassC(); // Ok
+//        ClassG g = (ClassG)a; // Runtime error
+//        g.print("hello");
+
+
+        // V - We lost track of the print(string, string) in C become it become a A first
+//        ClassA a = new ClassC(); // ok
+//        ClassG g = (ClassG)a; // Runtime error
+//        g.print("hello", "there");
+
+        // VI
+//        ClassA a = new ClassF(); // OK
+//        ClassC f = (ClassC)a; // Ok
+//        f.print(88, "there"); // Ok
+    }
+}

T5Q2-Marcus/src/ClassA.java

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+public class ClassA {
+    public void method1() {
+        System.out.println("ClassA.method1");
+    }
+
+    public void method2() {
+        System.out.println("ClassA.method2");
+    }
+}

T5Q2-Marcus/src/ClassB.java

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+public class ClassB extends ClassA {
+    public void method2() {
+        System.out.println("ClassB.method2");
+    }
+
+    public void method3() {
+        System.out.println("ClassB.method3");
+    }
+}

T5Q2-Marcus/src/ClassC.java

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+public class ClassC extends ClassB {
+    public void method3() {
+        System.out.println("ClassC.method3");
+    }
+
+    public void method4() {
+        System.out.println("ClassC.method4");
+    }
+}

T5Q2-Marcus/src/Main.java

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+public class Main {
+    public static void main(String[] args) {
+        // I
+//        ClassA a = new ClassB();
+//        ClassB b = (ClassB) a;
+//        b.method2(); // ClassB.method2
+//        b.method1(); // ClassA.method1
+
+        // II
+//        ClassA c = new ClassB();
+//        ClassC d = (ClassC) c; // Runtime error here
+//        d.method3(); // Never executed
+
+        // III
+//        ClassA e = new ClassC();
+//        ClassB f = (ClassB) e;
+//        f.method3(); // ClassC.method3
+//        f.method2(); // ClassB.method2
+//        f.method1(); // ClassA.method1
+
+        // IV
+//        ClassC g = (ClassC) new ClassA(); // Runtime error
+//        g.method1(); // never executed
+    }
+}

T5Q3/src/Polygon.java

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+//public abstract class Polygon {
+public class Polygon {
+    public enum KindofPolygon {
+        POLY_PLAIN,
+        POLY_RECT,
+        POLY_TRIANG
+    };
+    protected String name;
+    protected float width;
+    protected float height;
+    protected KindofPolygon polytype;
+
+    public Polygon(String theName, float theWidth, float theHeight) {
+        name = theName;
+        width = theWidth;
+        height = theHeight;
+        polytype = KindofPolygon.POLY_PLAIN;
+    }
+
+    public KindofPolygon getPolytype() {
+        return polytype;
+    }
+
+    public void setPolytype(KindofPolygon value) {
+        polytype = value;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public float calArea() {
+        return 0;
+    }
+
+    public void printWidthHeight( ) {
+        System.out.println("Width = " + width + " Height = " + height);
+    }
+
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T5Q3/src/Rectangle.java

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+public class Rectangle extends Polygon {
+    public Rectangle(String theName, float theWidth, float theHeight) {
+        super(theName, theWidth, theHeight) ;
+        this.polytype = KindofPolygon.POLY_RECT;
+    }
+
+    public float calArea() {
+        return width * height;
+    }
+}

T5Q3/src/TestPolygon.java

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+public class TestPolygon {
+    public static void printArea(Rectangle rect) {
+        float area = rect.calArea();
+        System.out.println("The area of the " + rect.getPolytype() + " is " + area);
+    }
+
+    public static void printArea(Triangle tri) {
+        float area = tri.calArea();
+        System.out.println("The area of the " + tri.getPolytype() + " is " + area);
+    }
+
+    public static void main(String[] args ) {
+
+        Rectangle rect = new Rectangle("Rectangle", 3.0f, 4.0f);
+        printArea(rect);  // static binding
+        rect.printWidthHeight();
+
+        Triangle triangle= new Triangle("Triangle", 3.0f, 4.0f);
+        printArea(triangle); // static binding
+        triangle.printWidthHeight();
+    }
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+    public static void printArea(Polygon poly) {
+        float area = poly.calArea( );
+        System.out.println("The area of the " + poly.getPolytype()  + " is " + area);
+    }
+
+    public static void main2(String[] args ) {
+
+        Rectangle rect = new Rectangle("Rectangle", 3.0f, 4.0f);
+        printArea(rect); // dynamic binding
+        rect.printWidthHeight();
+
+        Triangle triangle= new Triangle("Triangle", 3.0f, 4.0f);
+        printArea(triangle); // dynamic binding
+        triangle.printWidthHeight();
+    }
+}

T5Q3/src/Triangle.java

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+public class Triangle extends Polygon {
+    public Triangle (String theName, float theWidth, float theHeight) {
+        super(theName, theWidth, theHeight) ;
+        this.polytype = KindofPolygon.POLY_TRIANG;
+    }
+
+    public float calArea() {
+        return 0.5f * width * height;
+    }
+}