将两个列表合并成一个单独的列表

Question

I am trying to merge two lists into a seperate list. I know how to merge two lists, but I am not sure how to go about merging the values into an empty third list, without the values of the two lists changing.

list <int> FirstList, SecondList, ThirdList;

FirstList.merge(SecondList);

Answer 1

What you want is the generic merge algorithm, which copies from the two input ranges, rather than the specialized one for lists (which transfers the nodes into the third list):

std::merge(FirstList.begin(), FirstList.end(),
           SecondList.begin(), SecondList.end(),
           std::back_inserter(ThirdList));