2021.1.18 title:Login登入信息编写：for while和else语句、for和if判断语句；range函数、多次输入判断、断点编译

# DATE:2021.1.18 title:Login登入信息编写：for while和else语句、for和if判断语句；range函数、多次输入判断、断点编译

#range(开始值，结束值-1，步长)
#方法一：输出1-100之间的奇数
# for i in range(1,100,2):
#     print("loop:",i)
#方法二：输出1-100之间的奇数
# for i in range(1,100):
#     if i%2==1:
#         print("loop:",i)
#方法一：加个标志位，判定超过三次
user1="lisa"
passport1="lisa123"
passed_authentication=False
for i in range(3):
    user=input("user name:")
    passport=input("passport:")
    if user==user1 and passport==passport1:
        print("Welcome %s"%user)
        passed_authentication=True
        break
    else:
        print("invalid user or passport!")
if not passed_authentication:
    print("Try 3 times，stop！ for if")

#方法二：for  else 语句，判定超过三次
user1="lisa"
passport1="lisa123"
for i in range(3):
    user=input("user name:")
    passport=input("passport:")
    if user==user1 and passport==passport1:
        print("Welcome %s"%user)
        break
    else:
        print("invalid user or passport!")
else:#只要上面中间没有中断就执行else后代码
    print("Try 3 times，stop！for else")

#方法三：while  else 语句，判定超过三次
user1="lisa"
passport1="lisa123"
flag = 0
while flag < 3:
    user=input("user name:")
    passport=input("passport:")
    if user==user1 and passport==passport1:
        print("Welcome %s"%user)
        break1
    else:
        print("invalid user or passport!")
    flag += 1
else:#只要上面中间没有中断就执行else后代码
    print("Try 3 times，stop！while else")

# DATE:2021.1.18 title:断点执行和 多次输入
#方法四：for  else 语句，根据用户要求是否继续
'''user1="lisa"
passport1="lisa123"
count = 0
while count < 3:
    user=input("user name:")
    passport=input("passport:")
    if user==user1 and passport==passport1:
        print("Welcome %s"%user)
        break
    else:
        print("invalid user or passport!")
    count +=1
    if count == 3:
        keep_going = input("Are you try again?[y/n]")
        if keep_going == "y":
            count = 0
else:#只要上面中间没有中断就执行else后代码
    print("Try 3 times，stop！for else")'''

while  else 语句

user1="lisa"
passport1="lisa123"
i = 0
while i in range(4):
    user=input("user name:")
    passport=input("passport:")
    if user==user1 and passport==passport1:
        print("Welcome %s"%user)
        break
    else:
        print("invalid user or passport!")
    i +=1
    if i == 3:
        keep_going = input("Are you try again?[y/n]")
        if keep_going == "y":
            i = 0
else:#只要上面中间没有中断就执行else后代码
    print("Try 3 times，stop！for else")

给程序打断点执行：