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3#
發表於 2005-6-19 06:50 PM
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Originally posted by secretfj at 2005-6-19 06:37 PM:
$ v, S2 E! T. o' }1 u2 p3 P有無人知點解?' _2 ?- D/ Q+ K
Server 的Backup Code?
1 e, w( ?0 e8 ?! {4 G, t& P4 cso funny, thanks a lot! * m$ Q/ c- ?1 y6 l0 s2 V3 U
9 H* E! |# n7 @1 p
好簡單, ICQ 應該係 Visual C++ 寫的 , 而係 Visual C++ 入面& u2 u$ j% g" g# t
Maximum value for a variable of type "unsigned int" 係 4294967295 (0xffffffff) " {/ b M1 a, @5 z. y
個 value 過左呢個 range 就會 overflow , 佢只會理最後個32bits 數 (即係好似返返轉頭 , 循環咁); A0 P7 e' d6 s( }* z9 x7 x
e.g.
! m* N6 X2 V2 D, d" `1 A) F: o' C; L0 + 4294967295 = 4294967295 (max)5 v9 A4 }8 s# U" ~) ], e
1 + 4294967295 = 0 + 4294967296 = 0 (because of overflow)
" B F. e( j8 ]' q6 V J) yand so on....( b* y! H7 [. ?" u2 L
( L& i, M4 c! s% h$ |$ X+ d[ Last edited by gaye on 2005-6-19 at 06:57 PM ] |
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