第二天，三次登录
#用户登录3次机会
i = 0
while i < 3 :
username = input("请输入用户名：")
password = int(input("请输入密码："))
if username == 'cxr' and password ==123:
print('Sucessed')
else:
print('failed,plz try again')
i += 1
print('out')
占位符
#格式化输出 # % s d name = input('plz input name:') age = input('plz input age:') height = input('plz input height:') msg = "我叫%s，今年%s，身高%s" %(name,age,height) print(msg)