Stack based program 3 Write a Python Program to implement a Stack for the book details (bookno,bookname). That is, each item node of the stack contains two types of information- a book number and its name. Implement all the operations of Stack.

 

#source code:

def isEmpty(stk):

    if stk==[]:

        return True

    else:

        return False

def push(stk,item):

    stk.append(item)

    top=len(stk)-1

def pop(stk):

    if isEmpty(stk):

        print("underflow")

    else:

        item=stk.pop()

        if len(stk)==0:

            top=None

        else:

            top=len(stk)-1

        return item

def peek(stk):

    if isEmpty(stk):

        return "underflow"

    else:

        top=len(stk)-1

        return stk[top]

def display(stk):

    if isEmpty(stk):

        print("underflow")

    else:

        top=len(stk)-1

        print(stk[top],"<-top")

        for a in range(top-1,-1,-1):

            print(stk[a])

#main

stk=[]

top=None

while True:

    print("STACK OPERATIONS")

    print("1. Push")

    print("2. pop")

    print("3. peek")

    print("4. display")

    ch=int(input("enter choice"))

    if ch==1:

        bno=int(input("enter bookno to be inserted:"))

        bname=input("enter book name to be inserted:")

        item=[bno,bname]

        push(stk,item)

    elif ch==2:

        item=pop(stk)

        if item=="underflow":

            print("underflow")

        else:

            print("popped item is",item)

    elif ch==3:

        item=peek(stk)

        if item=="underflow":

            print("underflow")

        else:

            print("topmost item is:",item)

    elif ch==4:

        display(stk)

    else:

        print("invalid choice")

Output: