#include <iostream>
#include <string>
#include <iomanip>
#include <bitset>
#include <climits>

std::string conv_str_tobin(const std::string& s)
{
    std::string temps = "";
    
    for(unsigned int x = 0; x < s.size(); ++x)
    {
        //temps += conv<bool, std::string>(bin[x]);
        std::bitset<sizeof(char) * CHAR_BIT> bin(s[x]);
        temps += " "+bin.to_string();
    }
    return temps;
}

int main()
{   
    std::string s = "this is a test";
    std::cout << conv_str_tobin(s) << std::endl;
}