第十章课后习题

10-1和10-2：

with open('learning_python.txt') as file_object:
    contents=file_object.readlines()
for content in contents:
    print(content.rstrip())
for content in contents:
    print(content.replace('Python','C++').rstrip())

10-3：

name=input("Please enter your name: ")
with open('guest_book.txt','w') as file_object:
    file_object.write(name+'\n')

10-6和10-7：

print('Give me two numbers, and I will add them.')
print('enter q to quit.')
while True:
    first_number=input('First number: ')
    if first_number=='q':
        break
    second_number=input('Second number: ')
    try:
        answer=int(first_number)+int(second_number)
    except ValueError:
        print("Your input is not number.")
    else:
        print(answer)

10-12:

import json
def get_favorite_number():
    try:
        with open('number.json') as f_obj:
            favorite_number=json.load(f_obj)
    except FileNotFoundError:
        return None
    else:
        return favorite_number

def greet_user():
    user_favorite_number=input('What is your favorite number?')
    with open('number.json','w') as f_obj:
        json.dump(user_favorite_number,f_obj)
        print('I know your favorite number now!')
        

greet_user()
print("Your favorite number is "+get_favorite_number())