Question

Design a Python example that includes the following

Basic concepts:

• Loops
• Conditional statements

two of the advanced concepts: Encryption / Decryption, Lists / Dictionaries

Please leave a Description of the program

Answer 1

class library:
    books={1:"The fault in our stars",2:"The Alchemist",3:"The jungle book",4:"Rd sharma",5:"Science everyday",6:"gulliver's travel",7:"Kissing booth",8:"The power of subconsious mind"}
    lend={1:"khushi dubey"}
    avail={2:"The Alchemist",3:"The jungle book",4:"Rd sharma",5:"Science everyday",6:"gulliver's travel",7:"Kissing booth",8:"The power of subconsious mind"}
    def disp(cls):
        for item,var in cls.books.items():
            print(item,var)
        print("\n")    
    def addbook(cls,key,name):
        v=0
        for items in cls.books:
            if key==items:
                print("Book cannot be added.Change the key value\n")
                v=1
        if  v==0:
            cls.books.update({key:name})
            print("Book added to the library\n")   
        print("\n")
    def lend_book(cls,book_no,person):
        count=0
        i=0
        for item,var in cls.lend.items():
            if var==person:
                count=count+1
            elif item==book_no:
                i=1
        if count>=2:
            print("You cannot lend more than two books.Limit over!\n")
        elif i==1:
            print("This book is already lended.Choose some other book\n")
        else:
            cls.lend.update({book_no:person})
            for item,var in cls.books.items():
                if book_no!=item:
                     x=cls.books.get(item)
                     cls.avail.update({item:x})
        for (key) in set(cls.avail) & set(cls.lend):
             del cls.avail[key]
        print("\n")     
    def return_book(cls,book_no,person):
        a=0
        for item in list(cls.lend.keys()):
            if item==book_no:
                del cls.lend[item]
                print("Book returned\n")
                a=1
        if a==1:
            for item,var in cls.books.items():
                    if book_no==item:
                        x=cls.books.get(item)
                        cls.avail.update({item:x})
        else:
            print("book already returned\n")
    def availi(cls):
        print("Books available are:\n")
        for item,var in cls.avail.items():
            print(item,var)

if __name__=='__main__':
    b=library()
    print("Welcome to online library\n")
    while True:
        user_input=int(input("choose 1 to display the books\n2 to add a book\n3 to lend a book according to the availability\n4 to return the book\n"))
        if user_input==1:
            b.disp()
        elif user_input==2:
            book_id=int(input("enter book_id\n"))
            book_name=input("enter book name\n")
            b.addbook(book_id,book_name)
        elif user_input==3:
            b.availi()
            name=input("Enter your name\n")
            book_no=int(input("Enter book_id from the available books above\n"))
            b.lend_book(book_no,name)
        elif user_input==4:
            name=input("Enter your name\n")
            book_no=int(input("Enter book_id you have to return\n"))
            b.return_book(book_no,name)
        else:
            print("wrong input\n")

THIS IS A PROGRAM FOR A LIBRARY SYSTEM.ONE CAN ADD, DISPLAY,LEND AND RETURN A BOOK .ONE PERSON CANNOT LEND MORE THAN 2 BOOKS.HERE FOR LOOP, DICTIONARY AND CONDITIONAL STATEMENTS ARE USED.