Added OOP To Basic Python Doc

Docs/Basic/05-oop.md

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+# 05 – Object-Oriented Programming (OOP) in Python
+
+This document explains the basics of **Object-Oriented Programming (OOP)** in Python using simple examples.
+We cover:
+
+* Classes and objects
+* Attributes and methods
+* Class attributes vs instance attributes
+* Inheritance
+* Special (magic) methods
+
+---
+
+## 1. Basic Class, Attribute, and Method
+
+### Code
+
+```python
+class test_class():
+    def __init__(self, input):
+        self.parm = input
+        print("Class Created")
+
+    def result(self):
+        print(f"param is : {self.parm}") 
+
+var = test_class('abbas')
+var.result()
+```
+
+### Explanation
+
+#### Class
+
+* `test_class` is a **class**, which acts as a blueprint for creating objects.
+
+#### `__init__` method (Constructor)
+
+* `__init__` is a **special method** that runs automatically when a new object is created.
+* `input` is a **parameter** passed when creating the object.
+* `self.parm = input` creates an **instance attribute** called `parm`.
+
+#### Attribute
+
+* `parm` is an **attribute** (a variable that belongs to the object).
+* It stores data specific to each object.
+
+#### Method
+
+* `result()` is a **method** (a function that belongs to the class).
+* It uses `self.parm` to access the object’s data.
+
+#### Object Creation
+
+```python
+var = test_class('abbas')
+```
+
+* Creates an object named `var`.
+* Calls `__init__` automatically.
+
+#### Method Call
+
+```python
+var.result()
+```
+
+* Calls the `result` method on the object.
+
+---
+
+## 2. Class Attributes vs Instance Attributes
+
+### Code
+
+```python
+class test_class():
+    test_value = 'abbas'
+
+    def __init__(self, input):
+        self.parm = input
+        print("Class Created")
+
+    def result(self):
+        print(f"param is : {self.parm}") 
+
+var = test_class('abbas')
+var2 = test_class('mmd')
+
+var.result()
+var.test_value
+
+var2.test_value = 'mmd'
+var2.test_value
+var.test_value
+```
+
+### Explanation
+
+#### Class Attribute
+
+```python
+test_value = 'abbas'
+```
+
+* This is a **class attribute**.
+* It belongs to the class itself.
+* Shared by all objects unless overridden.
+
+#### Instance Attribute
+
+```python
+self.parm = input
+```
+
+* This is an **instance attribute**.
+* Each object has its own value.
+
+#### Behavior Analysis
+
+```python
+var.test_value
+```
+
+* Accesses the class attribute → `'abbas'`
+
+```python
+var2.test_value = 'mmd'
+```
+
+* Creates a **new instance attribute** for `var2`.
+* Does not change the class attribute.
+
+```python
+var2.test_value
+```
+
+* Returns `'mmd'` (instance attribute)
+
+```python
+var.test_value
+```
+
+* Still returns `'abbas'` (class attribute)
+
+#### Key Rule
+
+* Instance attributes override class attributes **only for that object**.
+
+---
+
+## 3. Inheritance
+
+### Code
+
+```python
+class class_1():
+    def __init__(self):
+        print("Class 1 Created") 
+
+    def hi(self):
+        print("Hi")
+
+class class_2(class_1):
+    def __init__(self):
+        print("Class 2 Created") 
+        self.hi()
+
+b = class_2()
+```
+
+### Explanation
+
+#### Parent Class
+
+```python
+class class_1():
+```
+
+* `class_1` is the **parent (base) class**.
+
+#### Child Class
+
+```python
+class class_2(class_1):
+```
+
+* `class_2` **inherits** from `class_1`.
+* It automatically has access to all public methods of `class_1`.
+
+#### Method Usage
+
+```python
+self.hi()
+```
+
+* `hi()` is defined in `class_1`.
+* Because of inheritance, `class_2` can call it.
+
+#### Output Order
+
+```text
+Class 2 Created
+Hi
+```
+
+#### Important Note
+
+* `class_1.__init__()` is **not called automatically** here.
+* To call it, you would need:
+
+```python
+super().__init__()
+```
+
+---
+
+## 4. Special (Magic) Methods
+
+### Code
+
+```python
+class class_1():
+    def __init__(self):
+        print("Class 1 Created") 
+
+    def __len__(self):
+        return 1
+
+    def __str__(self):
+        return 'print command on class'
+
+    def __del__(self):
+        return 'on del value'
+```
+
+### Explanation
+
+Special methods start and end with **double underscores (`__`)** and control built-in behavior.
+
+#### `__init__`
+
+* Runs when an object is created.
+
+#### `__len__`
+
+```python
+len(object)
+```
+
+* Defines the behavior of `len()` on the object.
+* Returns `1` in this example.
+
+#### `__str__`
+
+```python
+print(object)
+```
+
+* Defines the string representation of the object.
+* Used by `print()` and `str()`.
+
+#### `__del__`
+
+* Runs when the object is deleted or garbage-collected.
+* Used rarely in modern Python.
+* Return value is ignored.
+
+---
+
+## Summary
+
+* **Class**: Blueprint for objects
+* **Object**: Instance of a class
+* **Attribute**: Data stored in an object
+* **Method**: Function inside a class
+* **Class Attribute**: Shared across all objects
+* **Instance Attribute**: Unique per object
+* **Inheritance**: Child class reuses parent class logic
+* **Magic Methods**: Customize built-in Python behavior
+