C++ split std list into two lists

Question

Hey so I'm reasonably new into c++ and I ran into this problem where I want to split one std list of strings into two lists.

For example: list(1,2,3,4) -> list1(1,2) & list2(3,4)

I guess splice is what I am supposed to use for this, but I could not understand how that works at all...

Can someone please advice me how to do this?
Sorry about my bad English and thanks for help everyone.

Answer 1

Try the following

#include <iostream>
#include <list>
#include <string>
#include <iterator>

int main() 
{   
    std::list<std::string> lst1 = { "1", "2", "3", "4" };

    for (const auto &s : lst1 ) std::cout << s << ' ';
    std::cout << std::endl;

    std::cout << std::endl;

    std::list<std::string> lst2;
    lst2.splice( lst2.begin(), 
                 lst1, 
                 lst1.begin(), 
                 std::next( lst1.begin(), lst1.size() / 2 ) );

    for (const auto &s : lst2 ) std::cout << s << ' ';
    std::cout << std::endl;

    for (const auto &s : lst1 ) std::cout << s << ' ';
    std::cout << std::endl;
    return 0;
}

The output is

1 2 3 4 

1 2 
3 4 

The other approach

#include <iostream>
#include <list>
#include <string>
#include <iterator>

int main() 
{
    std::list<std::string> lst1 = { "1", "2", "3", "4" };

    for (const auto &s : lst1 ) std::cout << s << ' ';
    std::cout << std::endl;

    auto middle = std::next( lst1.begin(), lst1.size() / 2 );

    std::list<std::string> lst2( lst1.begin(), middle ); 

    std::list<std::string> lst3( middle, lst1.end() );

    for (const auto &s : lst2 ) std::cout << s << ' ';
    std::cout << std::endl;

    for (const auto &s : lst3 ) std::cout << s << ' ';
    std::cout << std::endl;
    return 0;
}

The output is

1 2 3 4 
1 2 
3 4