Add stack.py

Author: maliknaik16

data-structures/linked-lists/stack.py

@@ -0,0 +1,81 @@
+
+class Stack:
+
+ def __init__(self) -> None:
+ """
+ Initializes the stack.
+ """
+
+ self.stack = []
+ self.top = -1
+
+ def push(self, data) -> None:
+ """
+ Pushes an element onto the stack.
+ """
+
+ self.stack.append(data)
+ self.top += 1
+
+ def peek(self):
+ """
+ Returns the top of the stack element.
+ """
+
+ return self.stack[self.top]
+
+ def pop(self):
+ """
+ Pops the top element from the stack.
+ """
+
+ if not self.is_empty():
+ elm = self.stack.pop()
+ self.top -= 1
+
+ return elm
+ else:
+ print('Stack is empty')
+
+ def is_empty(self) -> bool:
+ """
+ Returns whether the stack is empty or not.
+ """
+
+ return self.top < 0
+
+ def get_stack(self) -> list:
+ """
+ Returns the complete stack.
+ """
+
+ return self.stack
+
+if __name__ == '__main__':
+
+ stack = Stack()
+
+ print('Pushing 2 onto the stack...')
+ stack.push(2)
+ print('Pushing 3 onto the stack...')
+ stack.push(3)
+ print('Stack Contents:', stack.get_stack())
+ print('Top of the stack:', stack.peek())
+ print('Popping top element...')
+ stack.pop()
+ print('Stack Contents:', stack.get_stack())
+ print('Pushing 1 onto the stack...')
+ stack.push(1)
+ print('Stack Contents:', stack.get_stack())
+
+# Result:
+# ---
+#
+# Pushing 2 onto the stack...
+# Pushing 3 onto the stack...
+# Stack Contents: [2, 3]
+# Top of the stack: 3
+# Popping top element...
+# Stack Contents: [2]
+# Pushing 1 onto the stack...
+# Stack Contents: [2, 1]