Linked List

//============================================================================
// Name        : Employee.cpp
// Author      : Zachary Standridge
// Version     :over a billion
// Copyright   : You wouldn't download a car would you?
// Description : Create and organize a list
//============================================================================

#include <iostream>

using namespace std;

struct  node
{
    int number;
    node *next;
};

bool isEmpty(node *head);
char menu();
void insertAsFirstElement(node *&head, node *&last, int number);
void insert(node *&head, node *&last, int number);
void remove(node *&head, node *&last);
void showList(node *current);

bool isEmpty(node *head)
{
    if(head == NULL)
        return true;
    else
        return false;
}
char menu()
{
    char choice;

    cout <<"Menu\n";
    cout <<"------------------\n";
    cout <<"1. Add Number\n";
    cout <<"2. Remove Number\n";
    cout <<"3. Show List\n";
    cout <<"4. Exit\n";

    cin >> choice;
    return choice;
}
void insertAsFirstElement(node *&head, node *&last, int number)
{
    node *temp = new node;
    temp ->number = number;
    temp ->next = NULL;
    head = temp;
    last = temp;
}
void insert(node *&head, node *&last, int number)
{
    if(isEmpty(head))
        insertAsFirstElement(head,last,number);
    else
        {
        node *temp = new node;
        temp ->number = number;
        temp ->next = NULL;
        last ->next = temp;
        last = temp;
        }
}
void remove(node *&head, node *&last)
{
    if (isEmpty(head))
        cout<<"There is nothing here\n";
    else if (head == last)
        {
        delete head;
        head == NULL;
        last == NULL;
        }
    else
    {
        node *temp = head;
        head = head->next;
        delete temp;
    }

}
void showList(node *current)
{
   if(isEmpty(current))
       cout<< "The list is empty.\n";
   else
   {
    cout << "The list contains : \n";
    while (current != NULL)
       {
           cout << current -> number << endl;
           current = current->next;
       }
   }
}

int main ()
{
    node *head = NULL;
    node *last = NULL;
    char choice;
    int number;
    do
        {
        choice = menu ();
        switch(choice)
               {
                case '1': cout<< "Please enter a number;";
                cin>>number;
                insert(head, last,number);
                break;
                case '2': remove (head, last);
                break;
                case '3': showList(head);
                break;
                default: cout<< "System exit\n";
               }
        }
        while(choice != '4');
    return 0;
}