June 2018 Update

Task/Classes/Elena/classes.elena

@@ -14,7 +14,7 @@ class MyClass
     ]
 }
 
-program =
+public program =
 [
     // instantiate the class
     var instance := MyClass new.

Task/Classes/Julia/classes.julia

@@ -0,0 +1,20 @@
+abstract type Mammal end
+habitat(::Mammal) = "planet Earth"
+
+struct Whale <: Mammal
+    mass::Float64
+    habitat::String
+end
+Base.show(io::IO, ::Whale) = print(io, "a whale")
+habitat(w::Whale) = w.habitat
+
+struct Wolf <: Mammal
+    mass::Float64
+end
+Base.show(io::IO, ::Wolf) = print(io, "a wolf")
+
+arr = [Whale(1000, "ocean"), Wolf(50)]
+println("Type of $arr is ", typeof(arr))
+for a in arr
+    println("Habitat of $a: ", habitat(a))
+end

Task/Classes/Processing/classes-1

@@ -0,0 +1,17 @@
+class ProgrammingLanguage
+{
+   // instance variable:
+   private String name;
+   // constructor (let's use it to give the instance variable a value):
+   public ProgrammingLanguage(String name)
+   {
+      this.name = name;
+      // note use of "this" to distinguish the instance variable from the argument
+   }
+   // a method:
+   public void sayHello()
+   {
+      println("Hello from the programming language " + name);
+      // the method has no argument or local variable called "name", so we can omit the "this"
+   }
+}

Task/Classes/Processing/classes-2

@@ -0,0 +1,5 @@
+// instantiate the class:
+ProgrammingLanguage processing = new ProgrammingLanguage("Processing");
+
+// call the method:
+processing.sayHello();