Added Encapsulation and improved Inheritance

rooky1905 · web-flow · commit 39304feaaf31 · 2020-10-02T21:20:01.000+05:30
I added critical component of OOPs in general, that is, Encapsulation and also improved Inheritance by making the User's method available to the Customer class and also explained concept of Encapsulation through practical example.
diff --git a/python_sandbox_finished/classes.py b/python_sandbox_finished/classes.py
@@ -2,33 +2,41 @@
 
 # Create class
 class User:
+
   # Constructor
   def __init__(self, name, email, age):
     self.name = name
     self.email = email
     self.age = age
+    
+    # Adding Encapsulation of variables... Encapsulation is the concept of making the variables non-accessible or accessible upto some extent from the child classes
+    self._private = 1000 # Encapsulated variables are declares with '_' in the constructor.
 
   def greeting(self):
-    return f'My name is {self.name} and I am {self.age}'
+      return f'My name is {self.name} and I am {self.age}'
 
   def has_birthday(self):
-    self.age += 1
-
+      self.age += 1
+ 
+ #function for encap variable
+  def print_encap(self):
+      print(self._private)
 
 # Extend class
 class Customer(User):
   # Constructor
   def __init__(self, name, email, age):
-    self.name = name
-    self.email = email
-    self.age = age
-    self.balance = 0
+      User.__init__(self, name, email, age) #Called proper parent class constructor to make this as proper child inehriting all methods.
+      self.name = name
+      self.email = email
+      self.age = age
+      self.balance = 0
 
   def set_balance(self, balance):
-    self.balance = balance
+      self.balance = balance
 
   def greeting(self):
-    return f'My name is {self.name} and I am {self.age} and my balance is {self.balance}'
+      return f'My name is {self.name} and I am {self.age} and my balance is {self.balance}'
 
 #  Init user object
 brad = User('Brad Traversy', 'brad@gmail.com', 37)
@@ -39,4 +47,17 @@ def greeting(self):
 print(janet.greeting())
 
 brad.has_birthday()
-print(brad.greeting())
+print(brad.greeting())
+
+#Encapsulation -->
+brad.print_encap()
+brad._private = 800 #Changing for brad
+brad.print_encap()
+
+# Method inherited from parent
+janet.print_encap() #Changing the variable for brad doesn't affect janets variable --> Encapsulation
+janet._private = 600
+janet.print_encap()
+
+#Similary changing janet's doesn't affect brad's variable.
+brad.print_encap()
