这些划分不知道什么意思?

happybean

Assume that you have a 10-character-wide ZIP code text box. What equivalence partitions would you create for this text box?
Key:
1.Valid 5-digit ZIP codes. Valid means that they're numeric digits, not that they are existing, in-use ZIP codes--although that could be another partition.
2.Valid 9-digit(9 digits with a dash) ZIP codes.
3.Short 5-digit. Have only 4 numbers, for example.
4.Short 9-digit. Have only 8 numbers, for example.
5.Long 5-digit. Have 8 digits without a dash, for example.
6.Long 9-digit. It maynot be possible to type in more than 9 digits and a dash, but you should try.
...
不知道这些划分是什么意思?

happybean

谢谢skinapi，我也明白了

skinapi

是有点绕，呵呵，不过总算看明白了，呵呵。
text box内容如下：
00000－0000
总共是10个符号，前面5个数字，第六个必须是－，后面还有4个数字，也就是9个数字加上“－”

文中划分等价类是：
1、5个数字
2、9个数字
3、小于5个数字
4、小于9个数字
5、大于5个数字
6、大于9个数字

happybean

那位高手解释一下啊

happybean

忘了说了text box内容如下：
00000－0000