Re: C/C++ question about dynamic "static struct"

From:

Ian Collins <ian-news@hotmail.com>

Newsgroups:

comp.lang.c++,comp.lang.c

Date:

Thu, 18 Oct 2012 12:19:39 +1300

Message-ID:

<ae8sobFo8jlU7@mid.individual.net>

On 10/18/12 10:47, gus gassmann wrote:

              myStruct = new MyStruct[ndim];
              for (int i=0; i< ndim; i++)
              {
                  myStruct[i] = {{(const)(get_str().c_str()), 0,
get_int()}};
              }

As others have correctly pointed out, the mistyped cast from std::string
will end in tears. You need to convert the string to an char array and
keep track of that data for later disposal.

Something like this my help:

struct FromString
{
   static std::vector<char*> stash;

   char *p;

   FromString( const std::string& s )
     : p(new char[s.size()])
   {
     s.copy(p, s.size());
     stash.push_back(p);
   }

   operator char*() const { return p; }
};

std::vector<char*> FromString::stash; // *free these later!!*

Then you could write:

   for (int i=0; i < ndim; i++)
   {
     MyStruct temp = {FromString(get_str()), 0, get_int()};
     myStruct[i] = temp;
   }

Note I kept the temporary variable to avoid the use C++11 extended
initialiser lists.

--
Ian Collins