this modification might solve ur prob

int main()
{

 char c, colon=',';
 ch= cin.get();
 while (ch = cin.get())
  {
    if (ch == colon)
    {
        ch ='.';
        ch=cin.get();
        if (ch == 'a')
           {
             ch=cin.get();
             if (ch=='n')
             {
              ch=cin.get();
              if (ch=='d')
                {
                 cin.ignore();
                 }
               }
            }
      }
     cout << ch;
   }
}



punkaj