Re: convert int to C string

On Fri, 29 Jun 2012 06:04:02 -0700, Andrej Viktorovich wrote:


You can't return a pointer to an *automatic* array (for that reason).


You can return a pointer to a static array, e.g.:

    char* intToStr(int value)
    {
        static char buffer[33];
        char* c = itoa(value,buffer,10);
        return buffer;
    }

but that isn't re-entrant, and you'll need to have finished using the
returned pointer before the next call to intToStr().

You can return a pointer to dynamically-allocated memory, e.g.:

    char* intToStr(int value)
    {
        char* buffer = malloc(33);
        char* c = itoa(value,buffer,10);
        return buffer;
    }

but then the caller has to explicitly free() the memory.

In C, having the caller pass in a suitably-sized buffer is usually the way
to go, so long as the caller can determine what is a suitable size without
too much effort.

In C++, you'd normally use a std::string rather than a char* (you can
then use the .c_str() method to get a char* for the data), e.g.:

    std::string intToStr(int value)
    {
        std::ostringstream os;
        os << value;
        return out.str();
    }