04-python-while(条件判断)

语法：

　　while 条件：

　　　　执行语句

　　　　break　　//通过 break 来终止语句

 

#无限循环
"""
while True:
    print("无限循环")
"""

#自增
"""
count = 1
flag = True

while flag:
    print(count)
    count += 1
"""

#加判断  从 1 到 100
"""
count = 1
flag = True

while flag:
    print(count)
    count += 1
    if count > 100:
        flag = False
"""


#从 1 加 到 100
num = 1
nums = 0
"""
while num<=100:
    num += 1
    nums += num
    print(nums)
"""
"""
while num<=100:
    nums += num
    num += 1
    print(nums)
"""

#while break 终止
"""
while True:
    print("one")
    print("two")
    print("three")
    print("four")
    break       #此处终止
    print("five")

b = 1
while True:
    print(b)
    b = b+1
    if b > 100:
        break
"""

#while continue 返回

num = 0
while num<=100:
    num += 1
    if num > 5 and num < 50:
        continue #到这里后无法继续执行 会返回结果给上面  除非条件不满足
    print(num)


#求 1 - 100 内的奇数
num = 0
while num <= 100:
    num += 1
    if num % 2 != 0:
        print(num)

#求 1 - 100 内的偶数
num = 0
while num <= 100:
    num += 1
    if num % 2 == 0:
        print(num)


#　　案例： 三次登陆

i = 0
while i < 3:
    userName = input("请输入账号：")
    passWord = int(input("请输入密码："))
    if userName == "cq" and passWord == 123:
        print("登陆成功")
        break
    else:
        print("登陆失败,请重试")
    i = i+1