stack-array-1.py

# Copyright (C) Deepali Srivastava - All Rights Reserved
# This code is part of DSA course available on CourseGalaxy.com  

class StackEmptyError(Exception):
    pass

class StackFullError(Exception):
    pass

class Stack:
    
    def __init__(self,max_size=10):
        self.items = [None] * max_size
        self.count = 0 

    def size(self):
        return self.count 

    def is_empty(self):
        return self.count == 0

    def is_full(self):
        return self.count == len(self.items)
    
    def push(self,x):
        if self.is_full():
            raise StackFullError("Stack is full, can't push")

        self.items[self.count] = x
        self.count+=1
            
    def pop(self):
        if self.is_empty():
            raise StackEmptyError("Stack is empty, can't pop")
             
        x = self.items[self.count-1]
        self.items[self.count-1] = None
        self.count-=1
        return x          

    def peek(self):
        if self.is_empty():
            raise StackEmptyError("Stack is empty, can't peek")

        return self.items[self.count-1] 
    
    def display(self):
        print(self.items)
     
##########################################################

if __name__ == "__main__":

    st = Stack(8)
    
    while True:
        print("1.Push") 
        print("2.Pop") 
        print("3.Peek") 
        print("4.Size")
        print("4.Display") 
        print("6.Quit") 
         
        choice = int(input("Enter your choice : "))

        if choice == 1:
            x=int(input("Enter the element to be pushed : "))
            st.push(x) 
        elif choice == 2:
            x=st.pop() 
            print("Popped element is : " , x) 
        elif choice == 3:
            print("Element at the top is : " , st.peek()) 
        elif choice == 4:
            print("Size of stack " , st.size()) 
        elif choice == 5:
            st.display() 
        elif choice == 6:
          break
        else:
          print("Wrong choice") 
        print()