Added stack.py

Author: VarunS2002

stack.py

@@ -0,0 +1,50 @@
+class Stack:
+    class EmptyStackError(Exception):
+        def __str__(self) -> str:
+            return "Stack is empty."
+
+    def __init__(self) -> None:
+        self._data: list[object] = []
+        self._size: int = 0
+
+    def __len__(self) -> int:
+        return self._size
+
+    def length(self) -> int:
+        return self.__len__()
+
+    def __str__(self) -> str:
+        return str(self._data)
+
+    def is_empty(self) -> bool:
+        return self._size == 0
+
+    def top(self) -> object:
+        if self.is_empty():
+            raise Stack.EmptyStackError
+        return self._data[-1]
+
+    def push(self, element: object) -> None:
+        self._data.append(element)
+        self._size += 1
+
+    def pop(self) -> object:
+        if self.is_empty():
+            raise Stack.EmptyStackError
+        self._size -= 1
+        return self._data.pop()
+
+
+if __name__ == '__main__':
+    stack = Stack()
+    print(stack.is_empty())
+    for i in range(10):
+        stack.push(i)
+    print(stack.top())
+    print(stack)
+    print(len(stack))
+    print(stack.length())
+    print(stack.is_empty())
+    for i in range(10):
+        print(stack.pop())
+    print(stack.is_empty())