What will be the output of the following C++ code?

#include <iostream>
#include <string>
#include <bitset>
using namespace std;
int main ()
{
    string mystring;
    bitset<4> mybits; 
    mybits.set();
    mystring = mybits.to_string<char, char_traits<char>, 
    allocator<char> >();
    cout << mystring << endl;
    return 0;
}