std::string.resize() and std::string.length()

Question

I\'m relatively new to C++ and I\'m still getting to grips with the C++ Standard Library. To help transition from C, I want to format a std::string using printf

Answer 1

My implementation for variable argument lists for functions is like this:

std::string format(const char *fmt, ...)
{
  using std::string;
  using std::vector;

  string retStr("");

  if (NULL != fmt)
  {
     va_list marker = NULL;

     // initialize variable arguments
     va_start(marker, fmt);

     // Get formatted string length adding one for NULL
     size_t len = _vscprintf(fmt, marker) + 1;

     // Create a char vector to hold the formatted string.
     vector buffer(len, '\0');
     int nWritten = _vsnprintf_s(&buffer[0], buffer.size(), len, fmt,
marker);

     if (nWritten > 0)
     {
        retStr = &buffer[0];
     }

     // Reset variable arguments
     va_end(marker);
  }

  return retStr;
}