#include <iostream>
#include <sstream>
#include <string>

namespace io {

    std::ostringstream stream;

    std::string string_printf(const char *s) {
        if (s != nullptr) {
            stream << s;
        }
        std::string rtval = stream.str();
        stream.str("");
        stream.clear();
        return rtval;
    }

    template <typename T, typename... Args>
    std::string string_printf(const char *s, T value, Args... args) {
        while (s && *s) {
            if (*s == '%' && *++s != '%') {
                stream << value;
                return string_printf(++s, args...);
            }
            stream << *s++;
        }
        if (sizeof...(args) > 0)
            throw std::runtime_error("Extra arguments...\n");
        std::string rt = stream.str();
        stream.str("");
        stream.clear();
        return rt;
    }
} // namespace io

int main() {
    std::string s = io::string_printf("test %s %d %f", "two", 10, 25.3f);
    std::cout << s << "\n";
    return 0;
}