练习题

1 n = 1
2 while n <10 :
3     if n == 7:
4         pass
5     else:
6         print(n)
7     n = n + 1

1 n = 0
2 v = 0
3 while n < 101:
4     v = v + n
5     n = n + 1
6 print(v)

1 n = 0
2 while n < 100:
3     if n % 2 == 0:
4         print(n)
5     else:
6         pass
7      n = n + 1

1 n = 0
2 while n < 100:
3     if n % 2 == 0:
4         pass
5     else:
6         print(n)
7      n = n + 1

1 n = 1
2 v = 0
3 while n < 100:
4     if n % 2 == 0:
5         v = v - n
6     else:
7         v = v + n
8     n = n + 1
9 print(v)

 1 n = 0
 2 while n < 3:
 3     user_name = input(‘请输入用户名:‘)
 4     password = input(‘请输入密码:‘)
 5     if user_name== ‘root‘ and password == ‘root‘:
 6         print(‘欢迎访问‘)
 7         break #跳出循环
 8     else:
 9         print(‘密码或用户名错误‘)
10         n = n + 1
11 else:
12     print(‘用户名和密码错误超过三次，‘)