Given below is the modified code for the question.
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#include <iostream>
using namespace std;

template <class T> class OrderedIterator; //forward declaration

template <class T>
class OrderedSet {
// =================
friend class OrderedIterator<T>;
int capacity; //maximum size of the container
int size; //number of actual elements in the container
T **buffer; //pointer to memory for holding elements

public:
OrderedSet(int aCapacity = 100);
OrderedSet(const OrderedSet<T> & c);
~OrderedSet();

typedef OrderedIterator<T> iterator;

int getSize() const {return size;} //answer number of elements
bool isFull()const {return size == capacity;} //answer if full

OrderedSet<T> & addLast( T & element); //add to end
OrderedSet<T> & addFirst( T & element); //add to front
T & removeLast();//remove last element
T & removeFirst(); //remove first element
OrderedSet<T> & remove(const T & element); //remove all items == element
iterator begin(void); //provide an start iterator
iterator end(void); //provide an end iterator
bool contains(const T &element); //checks if given element is present in set
void expand(); //doubles the capacity

void print(){
cout << "Set\n";
cout << "==========\n";
for(int i=0; i<size; i++) cout << *buffer[i];
}

};

template <class T>
class OrderedIterator { //The iterator class
// ===============
int index; //location in the container being iterated
OrderedSet<T> & s; //container being iterated

public:
OrderedIterator(OrderedSet<T> & set, int position = 0);
OrderedIterator<T> & operator++(int); //to advance to next element
T & operator*(); //to get element
bool operator==(const OrderedIterator<T> & iter);
bool operator!=(const OrderedIterator<T> & iter);
};


//Constructor Implementations
template <class T>
OrderedSet<T>::OrderedSet(int aCapacity)
: capacity(aCapacity),size(0), buffer(new T*[aCapacity]) {}

template <class T>
OrderedSet<T>::OrderedSet(const OrderedSet<T> & c)
: capacity(c.capacity), size(c.size), buffer(new T*[c.capacity]) {
for(int i=0; i< capacity; i++) buffer[i] = c.buffer[i];
}

template <class T>
OrderedSet<T>::~OrderedSet() {delete [] buffer; }
//Method Implementations

template <class T>
OrderedSet<T> & OrderedSet<T>::addLast(T & element){
if(!contains(element))
{
if(isFull())
expand();

buffer[size++] = &element;
}
return *this;
}

template <class T>
OrderedSet<T> & OrderedSet<T>::addFirst(T & element){

if(!contains(element))
{
if(isFull())
expand();
size++;
for(int i=size-1; i>0; i--) buffer[i] = buffer[i-1];
buffer[0] = &element;
}

return *this;
}

template <class T>
T & OrderedSet<T>::removeLast(){
return * buffer[size--];
}

template <class T>
T & OrderedSet<T>::removeFirst(){
T* temp;
size--;
temp = buffer[0];
for(int i=0; i<size; i++) buffer[i] = buffer[i+1];
return *temp;
}

template <class T>
OrderedSet<T> & OrderedSet<T>::remove(const T & item){

//remove all elements which are == item (assume T implements == oper)
int newIndex = 0;
for(int i=0; i<size; i++){
if(*buffer[i] != item) buffer[newIndex++] = buffer[i];
}
size = newIndex;
return *this;
}

template <class T>
bool OrderedSet<T>::contains(const T &element)
{
for(int i=0; i<size; i++)
{
if(*buffer[i] == element)
return true;
}
return false;
}


template <class T>
void OrderedSet<T>::expand()
{
capacity *= 2;
T** temp = new T*[capacity];
for(int i = 0; i < size; i++)
temp[i] = buffer[i];
delete buffer;
buffer = temp;
}
template <class T>
typename OrderedSet<T>::iterator OrderedSet<T>::begin(void) { //provide an start iterator
return OrderedIterator<T>(*this);
}

template <class T>
typename OrderedSet<T>::iterator OrderedSet<T>::end(void) { //provide an end iterator
return OrderedIterator<T>(*this, size);
}

template <class T>
OrderedIterator<T>::OrderedIterator(OrderedSet<T> & set, int position)
: index(position), s(set) {}

template <class T>
OrderedIterator<T> & OrderedIterator<T>::operator++(int) {
index++; return *this;
}

template <class T>
T & OrderedIterator<T>::operator*() {
return *(s.buffer[index]);

}

template <class T>
bool OrderedIterator<T>::operator==(const OrderedIterator<T> & iter) {
return (&s == &(iter.s)) && (index == iter.index);
}

template <class T>
bool OrderedIterator<T>::operator!=(const OrderedIterator<T> & iter) {
return !(*this == iter);
}


class BankAccount{
double balance;
string owner;
public:
BankAccount(string anOwner, double anAmount):owner(anOwner), balance(anAmount) {}
bool operator== (const BankAccount & b) {return owner == b.owner && balance == b.balance;}
bool operator!= (const BankAccount & b) {return !(*this == b);}
void printOn(ostream & o) const { o << owner << ": $" << balance << "\n"; }
};
ostream & operator<<(ostream & o, const BankAccount & b){
b.printOn(o);
return o;
}

//Example of how the collection and iterator could be used
int main() {
BankAccount b1("John", 100.0), b2("Bill", 50.0), b3("Robert", 200.0), b4("Alice",150.0);
OrderedSet<BankAccount> accounts(3); //initial capacity of 3, will expand when more added
accounts.addLast(b1).addLast(b2).addLast(b3).addLast(b4).addLast(b2); //b2 is duplicate and will not be added

for(OrderedSet<BankAccount>::iterator itr = accounts.begin();
itr != accounts.end(); itr++)

cout << *itr;
accounts.print();
accounts.remove(b2);
accounts.print();
return 0;
}//end main


output
======
John: $100
Bill: $50
Robert: $200
Alice: $150
Collection
==========
John: $100
Bill: $50
Robert: $200
Alice: $150
Collection
==========
John: $100
Robert: $200
Alice: $150