Question

You have a stack named BooksStack that contains records of books. Each book record is represented as a list containing book_title, author_name, and publication_year.

Write the following user-defined functions in Python to perform the specified operations on the stack BooksStack:

1. push_book(BooksStack, new_book): This function takes the stack BooksStack and a new book record new_book as arguments and pushes the new book record onto the stack.
2. pop_book(BooksStack): This function pops the topmost book record from the stack and returns it. If the stack is already empty, the function should display "Underflow".
3. peep(BookStack): This function displays the topmost element of the stack without deleting it. If the stack is empty, the function should display 'None'.

Answer 1

1. def push_book(BooksStack, new_book):
        BooksStack.append(new_book)

2. def pop_book(BooksStack):
       if not BooksStack:
          print("Underflow")
       else:
          return(BookStack.pop())

3. def peep(BooksStack):
      if not BooksStack:
         print("None")
      else:
         print(BookStack[-1])