C++: `std::string` convenient functions

spliting.cpp

#include <vector>
#include <string>
#include <numeric>

auto prettify(std::vector<std::string> const& v) {
    return "["
           + (v.empty() ? "" : ("'" + v.front() + "'"
                   + std::accumulate( v.begin() + 1, v.end(), std::string(),
                           [](std::string& s, auto const & t){ return std::move(s) + ", '" + t + "'";} )))
           + "]";
}

#include <iostream>
#include "utils.hpp"

int main() {
    auto v = split("  ");
    std::cout << prettify(split("                 ")) << "\n";
    std::cout << prettify(split(" 123  456 789    ")) << "\n";
    std::cout << prettify(split("123 456 789      ")) << "\n";
    std::cout << prettify(split("      123 456 789")) << "\n";
}

trimming.cpp

#include <iostream>
#include <vector>
#include <iomanip>

#include "utils.hpp"

int main() {
    std::vector<std::string> vec = {
            "monkey on the tree",
            "   castle on the cloud",
            "pig fly in the sky    ",
            "   the people are singing   ",
    };

    for (auto const& item : vec) {
        std::cout << std::quoted(trimmed(item)) << "\n";
    }
}

utils.hpp

#ifndef MY_CPP_STRING_UTILS_H
#define MY_CPP_STRING_UTILS_H

#include <string>

inline std::string trimmed(std::string const& str) {
    // _ a b c d e f _ _ ^
    // 0 1 2 3 4 5 6 7 8 9

    auto beginning = str.find_first_not_of(" \t");
    auto ending = str.find_last_not_of(" \t");

    if (beginning == std::string::npos) { beginning = 0; }

    if (ending == std::string::npos) {
        return str.substr(beginning);
    } else {
        return str.substr(beginning, ending - beginning + 1);
    }
}

#include <string>
#include <vector>

inline auto split(std::string const & s) {
    std::vector<std::string> result(1);
    for (auto const& t : s) {
        if (t != ' ') {
            result.back().push_back(t);
        } else if (!result.back().empty()) {
            result.emplace_back();
        }
    }
    if (result.back().empty()) result.pop_back();
    return result;
}

inline auto split(std::string const & s, char c) {
    std::vector<std::string> result(1);
    for (auto const& t : s) {
        if (t == c) {
            result.emplace_back();
        } else {
            result.back().push_back(t);
        }
    }
    return result;
}

#endif