adding some code for stack and queue in python

contents/stacks_and_queues/code/python/stack_queue.py

@@ -0,0 +1,95 @@
+class Node:
+    def __init__(self, val):
+        self.value = val
+        self.next = None
+
+
+class Stack:
+    def __init__(self):
+        self.stack_list = None
+
+    def push(self, val):
+        if self.stack_list is None:
+            self.stack_list = Node(val)
+        else:
+            temp = Node(val)
+            temp.next = self.stack_list
+            self.stack_list = temp
+
+    def pop(self):
+        if self.stack_list is None:
+            raise ValueError("Stack is empty")
+        else:
+            pop_val = self.stack_list.value
+            self.stack_list = self.stack_list.next
+            return pop_val
+
+    def get_top(self):
+        return self.stack_list.value
+
+    def print(self):
+        print("Current stack list : ")
+        temp = self.stack_list
+        while temp.next:
+            print(temp.value)
+            temp = temp.next
+        print(temp.value)
+
+
+class Queue:
+    def __init__(self):
+        self.queue_list = None
+
+    def enqueue(self, val):
+        temp = Node(val)
+        if self.queue_list is None:
+            self.queue_list = temp
+        else:
+            curr = self.queue_list
+            while curr.next:
+                curr = curr.next
+            curr.next = temp
+
+    def dequeue(self):
+        if self.queue_list is None:
+            raise ValueError("Queue is empty")
+        else:
+            temp = self.queue_list
+            dequeue_val = self.queue_list.value
+            self.queue_list = temp.next
+            return dequeue_val
+
+    def get_front(self):
+        curr = self.queue_list
+        while curr.next:
+            curr = curr.next
+        return curr.value
+
+    def print(self):
+        temp = self.queue_list
+        while temp.next:
+            print(temp.value)
+            temp = temp.next
+        print(temp.value)
+
+
+example_stack = Stack()
+example_stack.push(1)
+example_stack.push(2)
+example_stack.push(3)
+example_stack.print()
+print("you just pop ", example_stack.pop())
+
+example_stack.push(4)
+example_stack.print()
+print("current top => ", example_stack.get_top())
+
+example_queue = Queue()
+example_queue.enqueue(1)
+example_queue.enqueue(2)
+example_queue.enqueue(3)
+example_queue.print()
+example_queue.dequeue()
+example_queue.enqueue(4)
+example_queue.print()
+print("current front => ", example_queue.get_front())

contents/stacks_and_queues/stacks_and_queues.md

@@ -15,6 +15,12 @@ The notation for this depends on the language you are using. Queues, for example
 
 ## License
 
+## Example Code
+{% method %}
+{% sample lang="py" %}
+[import, lang:"python"](code/python/stack_queue.py)
+{% endmethod %}
+
 ##### Code Examples
 
 The code examples are licensed under the MIT license (found in [LICENSE.md](https://github.com/algorithm-archivists/algorithm-archive/blob/master/LICENSE.md)).