话说啊，所谓的C语言1000行，Java100行，Python20行呢。。。光一个登录就30行了。、 

一个输入用户名密码的登录程序：

init_usrname=input('Please enter initial username:')
init_password=input('Please enter initial password:')
print (init_usrname)
print (init_password)
flag0=0
flag1=0
print('>>>User Login<<<')while True:usr=input('enter username:')if usr==init_usrname:while flag0<3:password=input('enter password:')if password==init_password:print('Success Login!')flag1=1breakelse:flag0 +=1if flag0<=2:print('Wrong Password,enter again!')if flag1==1:breakflag0=0print ('You have tried three times,login again!')else:print ('Wrong Username,enter again!')