A+B=>A，没有考虑溢出的可能性，所以是有bug的。

所有跟帖： 

• 假设是unsigned。如果有a+b有overflow -g9- ♀ (137 bytes) () 12/21/2013 postreply 19:57:55

• u can get negative number. Same for + and - -inet-fan- ♂ (0 bytes) () 12/21/2013 postreply 20:59:34

• How would you get a negative number? -g9- ♀ (0 bytes) () 12/21/2013 postreply 21:03:33

• A=A XOR B, B= A XOR B, A = A XOR B, done -inet-fan- ♂ (0 bytes) () 12/21/2013 postreply 20:43:06

• 不错。是自己搞出来的？ -g9- ♀ (0 bytes) () 12/21/2013 postreply 21:14:29

• Come-on. That is an appetizer in interview -inet-fan- ♂ (140 bytes) () 12/22/2013 postreply 16:40:21

• 老大，🐂 -wxcmvyanyan- ♀ (0 bytes) () 12/21/2013 postreply 21:36:32

• 🐂是个啥东东？ -inet-fan- ♂ (0 bytes) () 12/22/2013 postreply 16:46:33