Implement stack using array

Author: AnushreeBagchi

implement_stack_using_array.py

@@ -0,0 +1,50 @@
+def create_array(initial_size):
+    arr = []
+    for i in range(initial_size):
+        arr.append(0)
+    return arr
+class Stack:
+    def __init__(self, initial_size = 10):
+        self.arr = create_array(initial_size)
+        self.next_index = 0
+        self.num_elements = 0
+    def push(self, data):
+        if self.next_index == len(self.arr):
+            print("out of space. Increasing arr capacity")
+            self.handle_capacity()
+        self.arr[self.next_index] = data
+        self.next_index += 1
+        self.num_elements += 1
+    def handle_capacity(self):
+        old_arr = self.arr
+        self.arr = [0 for _ in range (2* len(old_arr))]
+        for index, value in enumerate(old_arr):
+            self.arr[index] = value
+    def size(self):
+        return len(self.arr)
+    def is_empty(self):
+        return self.num_elements ==  0
+    def pop(self):
+        if self.is_empty():
+            self.next_index = 0
+            return None
+        last_element = self.arr[self.num_elements-1]
+        self.arr[self.num_elements-1] = 0
+        self.num_elements -= 1
+        self.next_index -= 1
+        return  last_element
+
+
+
+
+stack = Stack()
+stack.push("a")
+stack.push("b")
+print(stack.pop())
+
+print(stack.pop())
+print(stack.pop())
+
+
+
+