class Door:
  def open(self):
    print 'hello stranger'

def knock_door:
  a_door = Door()
  Door.open(a_door)

knock_door()

employe whatAreYouDoing.

employee whatIsYourName
employee whatIsYourDepartmentsName

// pseudo-code
function addValues( int x, int y )  return x + y
// call it
result = addValues( 8,8 )
print result // output is 16...

int addValues( int x, int y )
{
   return x + y;
}

public static int addValues( int x, int y ) {
    return x + y;
}

public class Employee {

    Department department;
    String name;

    public String whatsYourName(){
        return this.name;
    }
    public String whatsYourDeparmentsName(){
         return this.department.name();
    }
    public String whatAreYouDoing(){
        return "nothing";
    }
    // Ignore the following, only set here for completness
    public Employee( String name ) {
        this.name = name;
    }

}

// Usage sample.
Employee employee = new Employee( "John" ); // Creates an employee called John

// If I want to display what is this employee doing I could use its methods.
// to know it.
String name = employee.whatIsYourName():
String doingWhat = employee.whatAreYouDoint();

// Print the info to the console.

 System.out.printf("Employee %s is doing: %s", name, doingWhat );

Output:
Employee John is doing nothing.

f(x,y) = sin(x) + cos(y)

Z.g(x) = sin(x) + cos(Z.y)

result = mySum(num1, num2);

result = MyCalc.mySum(num1,num2);

class Example
{
   public int data = 0; // Each instance of Example holds its internal data. This is a "field", or "member variable".

   public void UpdateData() // .. and manipulates it (This is a method by the way)
   {
      data = data + 1;
   }

   public void PrintData() // This is also a method
   {
      Console.WriteLine(data);
   }
}

class Program
{
   public static void Main()
   {
       Example exampleObject1 = new Example();
       Example exampleObject2 = new Example();

       exampleObject1.UpdateData();
       exampleObject1.UpdateData();

       exampleObject2.UpdateData();

       exampleObject1.PrintData(); // Prints "2"
       exampleObject2.PrintData(); // Prints "1"
   }
}

# perfectly normal function
def hello(greetee):
  print "Hello", greetee

# generalise a bit (still a function though)
def greet(greeting, greetee):
  print greeting, greetee

# hide the greeting behind a layer of abstraction (still a function!)
def greet_with_greeter(greeter, greetee):
  print greeter.greeting, greetee

# very simple class we can pass to greet_with_greeter
class Greeter(object):
  def __init__(self, greeting):
    self.greeting = greeting

  # while we're at it, here's a method that uses self.greeting...
  def greet(self, greetee):
    print self.greeting, greetee

# save an object of class Greeter for later
hello_greeter = Greeter("Hello")

# now all of the following print the same message
hello("World")
greet("Hello", "World")
greet_with_greeter(hello_greeter, "World")
hello_greeter.greet("World")

Greeter.greet(hello_greeter, "World")

Greeter.greet2 = greet_with_greeter
hello_greeter.greet2("World")

public void DoSomething() {} // method
public int DoSomethingAndReturnMeANumber(){} // function

new Employer().calculateSum( 8, 8 );

var x = myFunction(4, 3);   // Function is called, return value will end up in x

function myFunction(a, b) {
    return a * b;          // Function returns the product of a and b
}

var message = "Hello world!";
var x = message.toUpperCase();
//Output: HELLO WORLD!

function person(firstName, lastName, age, eyeColor) {
    this.firstName = firstName;
    this.lastName = lastName;
    this.age = age;
    this.eyeColor = eyeColor;
    this.changeName = function (name) {
        this.lastName = name;
    };
}

something.changeName("SomeName"); //This will change 'something' objject's name to 'SomeName'