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

int main()
{
    // convert int to string
    {
        const int i = 12345 ;

        std::ostringstream stm ;
        stm << i ;

        const std::string str = stm.str() ;
        const char* cstr = str.c_str() ;
        std::cout << i << ' ' << str << ' ' << cstr << '\n' ;
    }

    // convert string to int
    {
        const std::string str = "-45678" ;
        std::istringstream stm(str) ;
        int i ;
        if( stm >> i ) std::cout << str << ' ' << i << '\n' ;
    }
}