Python基础-02-循环条件简单运用

1 .使用while循环输入1 2 3 4 5 6      8 9 10

i = 1
sum = 0
while i <= 10 :
    if i == 7:
        pass
    else :
    　　sum = sum + i
    　　i++

2.输出1-100内所有奇数

i = 1
sum = 0
while i <= 100:
    if i%2 == 0:
        pass
    else :
    　　sum = sum + i
    　　i++

3.求1-2+3-4+5...99的所有数和

i = 1
sum = 0
while i < 100:
    if i%2 == 1:
        sum = sum + i
    else:
        sum = sum - i
print (sum)

4.用户登录（三次机会重试）

count = 0
while count < 3:
    user =  input('>>>') 
    pwd = input('>>>') 
    if user == 'alex' and pwd == '1234':
        print('欢迎')
        break
    eles:
        print('密码错误')
    count++