About printing the accounts, you don't really seem to have got a handle on this object-oriented thing. A bankacct object should represent just one bank account, not the whole collection, so the print function should display only one account, i.e. "this" one. So you'd end up with something like:
Code:
void bankacct:print()
{
cout<<"Account number: "<<acc_num<<"\n";
cout<<"Balance: $"<<bal<<"\n\n";
}

//...

if (operation==4)
{
int ctr;

cout<<"Result: "<<num<<" existing accounts.\n";
for(ctr=0;ctr<num;ctr)
  account[ctr].print();
}