[問題] 暨南資工一題C++
#include <iostream>
int main()
{
unsigned s=555;
int i=(s>>4) & ~(~0<<3);
std::cout<<i;
system("PAUSE");
return 0;
}
我的算法是這樣：
unsigned s=555
也就是說二進位是0000001000101011
右移4bit後=0000000000100010
not 0=1
1左移3bit後=00000000000001000
not運算後 =11111111111110111
再 and 00000000000100010
-----------------
00000000000100010
轉回十進位=34
可是實際輸入電腦後答案是2...我哪裡做錯了嗎？
解答：
not 0=1111111111111111
左移3bit=1111111111111000
not後=0000000000000111
and 0000000000100010
-----------------
0000000000000010
轉成十進位後=2
我果然還太嫩了Orz
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