身份證的核對數位有11個可能性,所以計算身份證號碼時要用mod11(括號內的數字)
0 1 2 3 4 5 6 7 8 9 A
奇怪既係點解要有A?
點解唔直接用mod 10,唔用A呢?
身份證的核對數位
2006-11-23 5:33 am
回答 (2)
2006-11-23 5:40 am
✔ 最佳答案
因為係0（零）,樣子同英文MNOPQ的O冇分，所以為免混淆就用A2006-11-22 21:53:13 補充：
因為身份證的核對數位得一個位，加多一個位對電腦運算上多幾倍processing time. 而且check digit係最後出的結果，不用計算，可用charaters(英文字包括０，１，等字形－電腦的單位，咁０，１，A,B,C.....數落去有幾十個值，同兩個位數值０－９９一百個值相差不太大。
2006-11-23 5:51 am
mod10(n) = unit digit of n which is too easy to calculate.
Therefore, usually, use mod(11) for check digit and the result is not easy to calculate, but mod(11) must have 11 possible solutions and therefore, use A as the 11th solution.
Therefore, usually, use mod(11) for check digit and the result is not easy to calculate, but mod(11) must have 11 possible solutions and therefore, use A as the 11th solution.
收錄日期: 2021-05-03 12:57:01
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20061122000051KK04447