#_author:"ljk"
#date: 2017/5/25

# 1、break，中斷當前循環
# for i in range(10): #打印5-9
#     if i < 5:
#         continue #跳出當前循環
#     print(i)
#     for j in range(10):
#         print("layer2",j)
#         if j == 6:
#             break


#2 break 一次只能中斷一層循環
# for i in range(10): #打印5-9
#     if i < 5:
#         continue #跳出當前循環
#     print(i)
#     for j in range(10):
#         print("layer2",j)
#         if j == 6:
#             break
#     break #break一次最多只能中斷一層的循環，再中斷再break
#
#3

# exit_flag = False
# for i in range(10): #打印5-9
#     if i < 5:
#         continue #跳出當前循環
#     print(i)
#     for j in range(10):
#         print("layer2",j)
#         if j == 6:
#             exit_flag = True#如果沒有這一句，則運行結果同上，下一層循環不能執行
#             break
#     if exit_flag:#因為 exit_flag = True，所以才可以下一層的flag
#         break  #break一次最多只能中斷一層的循環，再中斷再break

# user1 = "ljk"
# password1 = "123"
# counter = 0
# while counter <3:
#     user = input("USER:")
#     password = input("PASSWORD:")
#     if user ==user1 and password == password1:
#         print("welcom")
#         break
#     else:
#         print("please try again")
#     counter += 1
#     if counter == 3:
#         keep_going = input("還想玩麽?[y/n]")
#         if keep_going == "y":
#             counter = 0
# else:  #while 循環正常結束後，會執行該else，如果break之後就不會執行
#     print("Stop!不要臉的！")

5.25 continue break for while