public boolean retainAll(Collection<?> c){
		if(c == null)
			return false;
		if(c.isEmpty()){
			clear();
			return true;
		}
		boolean modStatus = false;
		for(int i = 0; i < size; i++){
			if(!c.contains(elements[i])){
				remove(i);
				i--;
				modStatus = true;
			}
		}
		return (modStatus) ? true : false;
	}