stack.py

#Menu Driven Program to perform stack operations

Stack=list() # A default stack using list() function.

top=-1      # To know the current index position in stack.

#Adding element into a stack.

def Push_element(Stack,top):
    
    Ch='Y'
    
    while Ch == 'Y' or Ch == 'y'or Ch == 'Yes':
        
        val=input("Enter the value to be added in the stack: ")
        
        Stack.append(val) # Adding element into stack list.
        
        top += 1    # It checks the total number of addition.
        
        print ("Do you want to add more...<y/n>: ", end="")
        
        Ch = input()

        if Ch == 'N' or Ch == 'n' or Ch == 'No' or Ch == 'NO':
            
            break
        
    return top


#Removing stack elements

def Pop_element(Stack, top):

    slen = len(Stack)  # Finds total elements in the stack.

    if slen <= 0:     # Checks if stack is empty or not.
        
        print("Stack is empty")

    else:

        val = Stack.pop() # Removing from top of the stack.

        top = top-1

        print("Value deleted from stack is", val)

    return top

# Showing stack elements

def Show_element(Stack, top):

    slen = len(Stack)  # Finds total elements in the stack.

    if slen <= 0:    # Checks if stack is empty or not.

        print ("Stack is empty")

    else:

        print("The stack elements are...")

        i= top

        while (i >= 0):     # Stack elements processed in reverse order.

            print(Stack[i])

            i-=1


while (True):

    print()

    print ('STACK OPERATION')

    print ('-----------------')

    print ('1. Adding elements to a stack')

    print ('2. Removing elements from a stack')

    print ('3. Showing elements of a stack')

    print ('4. Exit from stack operation')

    print()

    Opt= int(input( "Enter your option: "))

    print()

    if (Opt == 1):

        #Push operation of stack - Adding element at top of the stack
        
        top =  Push_element(Stack, top)

    elif (Opt == 2):

        #Pop operation of stack - Deleting element
        
        top = Pop_element(Stack, top)

    elif (Opt==3):

        # Traversing / Showing stack element
        
        Show_element(Stack,top)

    elif (Opt==4):
        
        break