循环

死循环

while 1 == 1:
    print('right')

跳出死循环

count = 0
while count < 10:
    print('right')
    count = count + 1
print('循环结束')

 

continue 和break

count = 0
while count < 10:
   if count == 7:
        count = count + 1
        continue
           
print(count)

#continue 当前循环立即终止，直接进入下个循环，也就是说==7时 不打印count 

　

 

 

count = 0
while count < 10:
      count = count + 1
      print(count)
      break
print(count)
#break 终止所有循环 直接打印count

 

 

 练习

1、使用while 循环输入1 2 3 4 5 6     8 9 10

n = 1
while n < 11:
    if n == 7:
        pass
    else:
        print(n)
    n == n + 1

　　

2、求1-100的所有数的和

n = 1
s = 0
while n< 101:
    s = s + n
    n = n= 1 
print(s)

　　

3、输出1-100内所有奇数

n = 1

while n < 101:

　　temp = n % 2

　　if temp = 0:

　　　　pass
　　else:

　　print(n)

　　n = n + 1

　　

4、输出1-100内所有偶数

      参考3

5、求1-2+3-4+5....的所有数的和

n = 1
s = 0
while n < 100:
    temp = n % 2
    if temp == 0:
        s = s - n
    else:
        s = s + n
     n = n + 1
print(s)

　　

6、用户登录三次（三次机会重试）

 

count = 0
username = 'liu'
password  = '123'
while count < 3:
    user = input('用户名')
    pwd = input('密码')
    if user == username and pwd == password:
        print('欢迎你')
        break
    else:
        print('账号或密码错误')
    count = count + 1