if (obj1 instanceof Class1) { countClass1++; }

Week 6: Methods of OO Programming/12B. Count the Wizards [instanceof]

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+The program has again defined the class FairyTaleCharacter and its derived classes Wizard, Nephew, and Superhero.
+
+Write a method:
+public static int countWizards(ArrayList<FairyTaleCharacter> characters)
+that takes a list of different fairy tale characters as a parameter 
+and returns the number of wizards in the list as an integer.
+
+
+
+
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Random;
+
+public class Test {
+    public static void main(String[] args){
+        final Random r = new Random();
+        
+        for (int test=1; test<=3; test++) {
+            
+            System.out.println("Test " + test);
+            
+            int age = r.nextInt(5) + 5;
+            ArrayList<Integer> ages = new ArrayList<>();
+            for (int i=0; i<20; i++) {
+                ages.add(age);
+                age += r.nextInt(10) + 1;
+            }
+            
+            ArrayList<FairyTaleCharacter> characters = new ArrayList<>();
+            String[] colors = "blue yellow red black brown white green".split(" ");
+            
+            for (String name : new String[] {"Benny", "Rupert", "Milo", "Charlie"}) {
+                String color = colors[r.nextInt(colors.length)];
+                characters.add(new Nephew(name, ages.remove(r.nextInt(ages.size())), color));
+            }
+            
+            String[] superpowers = "super vision flight super strength reading ability super sneeze".split(" ");
+            for (String name : new String[] {"Manbat", "Mouseman", "Bulk", "Copperman", "Steelcat"}) {
+                String power = superpowers[r.nextInt(superpowers.length)];
+                characters.add(new Superhero(name, ages.remove(r.nextInt(ages.size())), power));
+            }
+            
+            ArrayList<FairyTaleCharacter> wizards = new ArrayList<>();
+            String[] wands = "oak licorice birch alder walnut plastic".split(" ");
+            for (String name : new String[] {"Harry", "Hermione", "Ron", "Voldemort", "Dumbledore", "Snape"}) {
+                String wand = wands[r.nextInt(wands.length)];
+                wizards.add(new Wizard(name, ages.remove(r.nextInt(ages.size())), wand));
+            }
+            
+            int ch = r.nextInt(characters.size());
+            int wz = r.nextInt(wizards.size());
+            
+            Collections.shuffle(characters, r);
+            Collections.shuffle(wizards, r);
+            
+            ArrayList<FairyTaleCharacter> testList = new ArrayList<>();
+            
+            for (int i=0; i<ch; i++) {
+                testList.add(characters.get(i));
+            }
+            
+            for (int i=0; i<wz; i++) {
+                testList.add(wizards.get(i));
+            }
+            
+            Collections.shuffle(testList, r);
+            
+            System.out.println("Fairy Tale Characters:");
+            testList.stream().forEach(c -> System.out.println("" + c));
+            
+            System.out.println("Wizards: " + countWizards(testList));
+            
+            System.out.println("");
+        }
+    }
+    
+
+    //ADD
+    public static int countWizards(ArrayList<FairyTaleCharacter> characters) {
+        int countWizards = 0;
+        for (FairyTaleCharacter character : characters) {
+            if (character instanceof Wizard) {
+                countWizards++;
+            }
+        }
+        return countWizards;
+    }
+
+
+
+
+
+
+
+
+
+}
+
+
+
+
+class FairyTaleCharacter {
+    private String name;
+    private int age;
+    
+    public FairyTaleCharacter(String name, int age) {
+        this.name = name;
+        this.age = age;
+    }
+    
+    public String getName() {
+        return name;
+    }
+    
+    public int getAge() {
+        return age;
+    }
+    
+    @Override
+    public String toString() {
+        return name + ", " + age + " years";
+    }
+}
+
+
+
+
+class Nephew extends FairyTaleCharacter {
+    private String capColor;
+
+    public Nephew(String name, int age, String capColor) {
+        super(name, age);
+        this.capColor = capColor;
+    }
+
+    @Override
+    public String toString() {
+        return super.toString() + ", " + capColor + " cap (nephew)";
+    }
+}
+
+
+
+
+class Wizard extends FairyTaleCharacter {
+    private String wand;
+
+    public Wizard(String name, int age, String wand) {
+        super(name, age);
+        this.wand = wand;
+    }
+    
+    @Override
+    public String toString() {
+        return super.toString() + ", wand: " + wand + " (wizard)";
+    }
+}
+
+
+
+
+class Superhero extends FairyTaleCharacter {
+    private String superpower;
+
+    public Superhero(String name, int age, String superpower) {
+        super(name, age);
+        this.superpower = superpower;
+    }
+    
+    @Override
+    public String toString() {
+        return super.toString() + ", superpower: " + superpower + " (superhero)";
+    }
+}
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Test 1
+Fairy Tale Characters:
+Rupert, 111 years, white cap (nephew)
+Milo, 69 years, blue cap (nephew)
+Hermione, 105 years, wand: alder (wizard)
+Steelcat, 42 years, superpower: flight (superhero)
+Manbat, 98 years, superpower: super (superhero)
+Snape, 50 years, wand: alder (wizard)
+Wizards: 2
+
+Test 2
+Fairy Tale Characters:
+Steelcat, 54 years, superpower: vision (superhero)
+Manbat, 32 years, superpower: flight (superhero)
+Hermione, 88 years, wand: birch (wizard)
+Mouseman, 33 years, superpower: super (superhero)
+Rupert, 53 years, green cap (nephew)
+Wizards: 1
+
+Test 3
+Fairy Tale Characters:
+Benny, 27 years, blue cap (nephew)
+Copperman, 43 years, superpower: super (superhero)
+Rupert, 140 years, green cap (nephew)
+Steelcat, 108 years, superpower: super (superhero)
+Mouseman, 120 years, superpower: flight (superhero)
+Wizards: 0
+
+
+
+
+