沒有意義的類?事實(shí)上STL中的函數(shù)對(duì)象就是通過這種方式實(shí)現(xiàn)的@笨笨

這個(gè)問題thinking in c++提到過.
One of the fundamental rules of objects is that each object must have a unique address, so structures with no data members will always have some minimum nonzero size.