feat(readme) add documentation for alogithm stack class

.gitignore

@@ -112,3 +112,4 @@ dmypy.json
 
 # Pyre type checker
 .pyre/
+*.vscode

README.md

@@ -1,2 +1,36 @@
 # Python-Data-Structures-and-Algorithms
 
+# Stack class
+
+This is a Python class that implements a stack data structure. A stack is a linear data structure in which elements are added and removed from one end, called the top. The stack follows the last-in, first-out (LIFO) principle, which means that the last element added to the stack is the first element to be removed.
+
+The `Stack` class has the following methods:
+
+* `__init__(self)`: Initializes the stack.
+* `is_empty(self)`: Returns True if the stack is empty, False otherwise.
+* `push(self, item)`: Adds an item to the stack.
+* `pop(self)`: Removes an item from the stack and returns it.
+* `peek(self)`: Returns the top item on the stack without removing it.
+* `size(self)`: Returns the number of items in the stack.
+* `__str__(self)`: Returns a string representation of the stack.
+
+Here is an example of how to use the `Stack` class:
+python
+>>> s = Stack()
+>>> print(s)
+[]
+>>> print(s.is_empty())
+True
+>>> s.push(1)
+>>> s.push(2)
+>>> s.push(3)
+>>> print(s)
+[1, 2, 3]
+>>> print(s.pop())
+3
+>>> print(s.peek())
+2
+>>> print(s.size())
+2
+The `Stack` class is a useful data structure for implementing a variety of algorithms, such as the infix-to-postfix conversion algorithm and the binary search algorithm.
+You can view code here [stack class](/Starting Files/a_star.py)