print('1、使用while循环输入 1 2 3 4 5 6     8 9 10')

 i = 1

 while i < 10:

     i += 1

     if i == 7:

          continue       #print(' ')这两个可以替换一下，看看不同的效果

     else:

         print(i)

 print('2、求1-100的所有数的和')

 i = 0

 sum = 0

 while i < 100:

       i += 1

       sum = sum + i

       print(sum)

 print('3、输出 1-100 内的所有奇数')

 i = 0

 while i < 100:

     i += 1

     if i %2 != 0:

         print(i)

 print('4、输出 1-100 内的所有偶数')

 i = 0

 while i < 100:

     i += 1

     if i %2 == 0:

         print(i)

 print('5、求1-2+3-4+5 ... 99的所有数的和')

 i = 0

 sum = 0

 j = -1

 while i < 99:

     i += 1

     if i %2 != 0:

         sum = sum + (i * (-j))

     if i %2 == 0:

         sum = sum + (i * j)

 print(sum)

 print('6、用户登陆（三次机会重试）')

 i = 0

 name = 'allison'

 password = ''

 while i < 3:

     na = input('请输入用户名：')

     pw = input('请输入密码：')

     i += 1

     oppo = 3 - i

     if na == name and pw == password:

         print('输入正确')

         break

     elif na != name or pw != password:

         print('输入错误， 还有%d次机会'%(oppo))

         if i == 3:

             answer = input('输入Y再试试？')

             if answer == 'Y':

                 print('再来三次机会')

                 i = 0

             else:

                 print('机会已用完')