How might I go about doing the following in C++?:

Define vectors "v" and "w" (doesn't really matter what they are) and then redefine "v" as the concatenation of "v" and "w".

For example, if I have v = [1,2,3] and w = [4,5,6], I want to redefine v = [v,w] = [1,2,3,4,5,6].