http://www.cppblog.com/converse/archive/2006/07/10/9664.html
bool Is2Power(int nNum)
{
return nNum > 0 ? ((nNum & (~nNum + 1)) == nNum ? true : false) : false;
}
或者
#define IS_POWER_OF_2(v) (!((v) & ((v) - 1)) && (v))
http://www.cppblog.com/converse/archive/2006/07/10/9664.html
bool Is2Power(int nNum)
{
return nNum > 0 ? ((nNum & (~nNum + 1)) == nNum ? true : false) : false;
}
或者
#define IS_POWER_OF_2(v) (!((v) & ((v) - 1)) && (v))