int serve_level(string riddle, string answer, string allowable_chars) {
bool correct_answer = false;
int player_input_1;
char player_input_2;
LList<char> l;
cout << riddle << endl;
while(!correct_answer) {
player_input_1 = 0;
cout << "Available letters: " << allowable_chars << endl;
cout << "Choose something to do to the list: " << endl;
cout << "[1] to Append a letter to the back of the list. " << endl;
cout << "[2] to Push a letter to the front of the list. " << endl;
cout << "[3] to Delete a letter from the list. " << endl;
cout << "The list will be printed out each time you modify it. " <<endl;
cin >> player_input_1;
if(player_input_1 == 1) {
cout << "Select a letter to append. " << endl;
cin >> player_input_2;
if(allowable_chars.find(player_input_2) != string::npos) {
l.append(player_input_2);
cout << player_input_2 << " appended to the list! " << endl;
l.print();
} else {
cout << "Please use a valid letter! ";
}
} else if(player_input_1 == 2) {
void enqueue(const E it)
{
queue->append(it);
++length;
}
