Chapter03/problem_26 alternative solution

[ppuedom]

About the proposed solution on https://github.com/PacktPublishing/The-Modern-Cpp-Challenge/blob/master/Chapter03/problem_26/main.cpp

Maybe a bit more compact solution could be:

#include <iostream>
#include <vector>
#include <sstream>
#include <cassert>

using namespace std;

template <typename C>
string join_strings(C const & c, const char delimiter) {
    ostringstream oss;
    for (const auto &i : c) {
        if(oss.tellp()) oss << delimiter;
        oss << i;
    }
    return oss.str();
}

int main()
{
    auto l1 = {"one"s, "two"s, "three"s};
    assert(join_strings(l1,' ') == "one two three"s );
    auto l2 = {""s};
    assert(join_strings(l2,' ') == ""s );
    auto l3 = vector<string>();
    assert(join_strings(l3,' ') == ""s );
    auto l4= vector<string> {"one"}; // C str
    assert(join_strings(l4,' ') == "one"s );
    return 0;
}