How to use the code from Antti Laaksonen's book?

Question

C++ / C#

I am studying A. Laaksonen's book "Olympiad Programming". There's a problem about generating subsets, and the following algorithm is given:

The function manipulates a vector subset that contains the elements of the subset. To start the search, we call the function with parameter 1.

void search(int k){
if (k == n + 1){
    //обработать подмножество
} else{
    //включить k в подмножество
    subset.push_back(k);
    search(k+1);
    subset.pop_back();
    search(k+1);
    //не включить k в подмножество
}}

It is not clear to me how to use this code, I would like to see the whole file. And so I do not know how to apply this code to figure it out.