Thread: oparator new

Why do I get always 4 for strlen(buf) ?

Code:

int  main()
{
   int i = 1;
   char * buf ;

   while(i<11)
   {
        buf = new char[i++];
        strcat(buf, "a");
        cout << strlen(buf) <<"\n";
   }

   delete [] buf;

   return  0;
}