char** array = 0; // 2d array of strings
int arraysize = 0; // current number of rows in the array
int elmsused = 0; // number of rows actually used
const int BLOCKSIZE = 10;
 
string line;
ifstream in("file.txt");
while( getline(in, line) )
{
      if( elmsused == arraysize)
      {
             array = (char **)realloc(array, arraysize+BLOCKSIZE);
             arraysize += BLOCKSIZE);
      }
      array[elmsused] = (char *)malloc(line.size()+1);
      strcpy(array[elmsused], line.c_str());
      elmsused++;
}