------------- Interactive.h ------------
#ifndef INTERACTIVE_H
#define INTERACTIVE_H

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

class Interactive
{
private:
   std::stringstream m_sin;
public:
    void read(std::string input);
    void write(std::string output);
    void parseCommand(std::string input);
};

#endif



-------------Interactive.cpp ---------------

#include "Interactive.h"
#include <string>
#include <sstream>
#include <iostream>

void Interactive::parseCommand(std::string input)
{
    m_sin >> input;
    std::cout << m_sin.str();
}

void Interactive::read(std::string input){}
void Interactive::write(std::string output){}

------------- main.cpp -----------------
#include "Interactive.h"

int main()
{
    Interactive interface;

    interface.parseCommand("ahoj");

    return 0;
}