~~~~练习~~~~问路程序

person=['B','C','D','E']
know=False
def askway(address):
    #问路
    if len(person)>0 and know is False:
        name=person.pop()
        def ask():
            print('%s,你知道%s怎么走吗？'%(name,address))
            answer=input()
            if answer=='Y':
                know=True
                answer_address=input('请输入具体地址')
                print('%s知道%s怎么走，具体为%s'%(name,address,answer_address))
            else:
                print('%s不知道，请询问下一个人'%name)
                askway(address)
        ask()
    else:
        print('没有人知道')
x='nanjing'        
askway(x)