#include <iostream>
#include <cstdlib>
using namespace std;


class link
{
public:
    int num;
    link *ptr;
    void add();
    void del();
    void ins();
    void disp();
    void end();
};

link *start = NULL;
link *current;
int choice1;
int dispchoice;
int choice;

int main()
{
    link list;
    start = NULL;

    cout<<"\t\t##MENU##"<<endl;
    cout<<"\tPress 1 to Continue"<<endl;
    cout<<"\tPress 0 to Exit"<<endl;
    cin>>choice;

    system ("cls");

    switch(choice)
    {
    case 1: do
            {
                cout<<"\t\t##MENU##"<<endl;
                cout<<"[1]Add Element"<<endl;
                cout<<"[2]Insert Element"<<endl;
                cout<<"[3]Delete Element"<<endl;
                cout<<"[4]Display List"<<endl;
                cout<<"[0]Exit"<<endl;
                cout<<"Enter Your Choice: ";
                cin>>choice1;

                system ("cls");

                switch (choice1)
                {
                case 1: system ("cls");
                    link.add();
                    break;
                case 2: system ("cls");
                    link.ins();
                    break;
                case 3: system ("cls");
                    link.del();
                    break;
                case 4: system ("cls");
                    link.disp();
                    break;
                case 0: system ("cls");
                    link.end();
                    break;
                }
            }while (choice > 4);
            system ("cls");
            break;
    case 0: system ("cls");
            link.end();
            break;
    }

return 0;
}
void link::add()
{
    link *temp1, *temp2;

    temp1 = new link;

    cout<<"Enter The Number to be Added on the List: ";
    cin>>temp1->num;

    if (start == NULL)
    {
        start = temp1;
        current = start;
    }
    else
    {
        temp2 = start;
        while (temp2->ptr != NULL)
        {
            temp2 = temp2->ptr;
        }
        temp2->ptr = temp1;
    }
    system ("cls");
    
    return;
}
void link::disp()
{
    link *temp;
    temp = start;
    
    if (temp == NULL)
    {
        cout<<"Empty List..."<<endl;
        system ("cls");
    }
    else
    {
        while (temp != NULL)
        {
            cout<<"Number: "<<temp->num<<endl;
            if (temp == current)
                temp = temp->ptr;
        }
    }
    
    return;
}
void link::end()
{
    cout<<"Thank You..."<<endl;
    return;
}
void link::del()
{
    link *temp1, *temp2;

    if (start == NULL)
        cout<<"Empty List..."<<endl;
    else
    {
        temp1 = start;
        if (temp1->ptr == NULL)
        {
            delete temp1;
            start = NULL;
        }
        else
        {
            while (temp1->ptr != NULL)
            {
                temp2 = temp1;
                temp1 = temp1->ptr;
            }
            delete temp1;
            temp2->ptr = NULL;
        }
    }

    return;
}