Write a menu driven program to create a linked list and to perform insert and delete operations

#include

#include

#include

#include

#include

int insbeg(int item);

int inspos(int item);

int insend(int item);

int delbeg();

int delpos();

int delend();

struct node

{

            int info;

            struct node *link;

};

typedef struct node n1;

n1 *start = NULL;

n1 *currptr, *newnode, *preptr;

class list

{

            public:

                        int create();

                        int display();

                        int ins();

                        int del();

};

int list::create()

{

            char ch;

            start = new n1;

            currptr = start;

            while (1)

            {

                        cout << "\nEnter the item value :\t" ;

                        cin >> currptr->info;

                        cout << "\nContinue? (y/n) : " ;

                        flushall();

                        cin >> ch;

                        if (ch=='y')

                        {

                                    newnode = new n1;

                                    currptr->link = newnode;

                                    currptr = newnode;

                        }

                        else

                        {

                                    currptr->link = NULL;

                                    break;

                        }

            }

            return 0;

}

int list::display()

{

            if (start==NULL)

            {

                        cout << "\nEmpty list" ;

                        exit(0);

            }

            else

            {

                        currptr = start;

            }

            cout << "\nThe list is : \n" ;

            while (currptr->link!=NULL)

            {

                        cout << currptr->info;

                        cout << "--->" ;

                        currptr = currptr->link;

            }

            cout << currptr->info;

            cout << "--->" ;

            cout << "NULL" ;

            return 0;

}

int list::ins()

{

            int ch, item;

            cout << "\nEnter the item to insert :\t" ;

            cin >> item;

            newnode = new n1;

            cout << "\n\nChoose any given option : ";

            cout << "\n\t 1. At the beginning" ;

            cout << "\n\t 2. At a position" ;

            cout << "\n\t 3. At the end";

            cout << "\n\nEnter your choice :\t" ;

            fflush(stdin);

            cin >> ch;

            switch (ch)

            {

            case 1: insbeg(item);

                                                  break;

            case 2: inspos(item);

                                                  break;

            case 3: insend(item);

                                                  break;

            default: cout << "\nInvalid choice" ;

            }

            return 0;

}

insbeg(int item)

{

            newnode->info = item;

            newnode->link = start;

            start = newnode;

            return 0;

}

inspos(int item)

{

            int i, pos;

            currptr = start;

            cout << "\nEnter the position :\t" ;

            cin >> pos;

            if (pos==1)

            {

                        insbeg(item);

            }

            else

            {

                        for (i=1 ;i

                        {

                                    currptr = currptr->link;

                        }

                        newnode->link = currptr->link;

                        newnode->info = item;

                        currptr->link = newnode;

            }

            return 0;

}

insend(int item)

{

            currptr =start;

            if (start->link==NULL)

            {

                        currptr->link = newnode;

                        newnode->info = item;

                        newnode->link = NULL;

            }

            else

            {

                        while (currptr->link!=NULL)

                        {

                                    currptr = currptr->link;

                        }

                        currptr->link = newnode;

                        newnode->info = item;

                        newnode->link = NULL;

            }

            return 0;

}

int list::del()

{

            int cho;

            cout << "\n\nChoose any given option : ";

            cout << "\n\t 1. Delete from beginning" ;

            cout << "\n\t 2. Delete from position" ;

            cout << "\n\t 3. Delete from end";

            cout << "\n\nEnter your choice :\t" ;

            fflush(stdin);

            cin >> cho;

            switch (cho)

            {

            case 1: delbeg();

                                                  break;

            case 2: delpos();

                                                  break;

            case 3: delend();

                                                  break;

            default: cout << "\nInvalid choice" ;

            }

            return 0;

}

delbeg()

{

            currptr =start;

            start = currptr->link;

            delete currptr;

            return 0;

}

delpos()

{

            int i, pos;

            cout << "\nEnter the position :\t" ;

            cin >> pos;

            if (pos==1)

            {

                        delbeg();

            }

            else

            {

                        currptr = start;

                        preptr = NULL;

                        for (i=1 ;i

                        {

                                    preptr = currptr;

                                    currptr = currptr->link;

                        }

                        preptr->link = currptr->link;

                        delete currptr;

            }

            return 0;

}

delend()

{

            currptr =start;

            if (start->link==NULL)

            {

                        start = NULL;

                        delete currptr;

            }

            else

            {

                        preptr = NULL;

                        while (currptr->link!=NULL)

                        {

                                    preptr = currptr;

                                    currptr = currptr->link;

                        }

                        preptr->link = NULL;

                        delete currptr;

            }

            return 0;

}

void main()

{

            list obj;

            int ch1;

            char ch2;

            clrscr();

            cout << "\nCreate a linked list" ;

            obj.create();

            do

            {

                        cout << "\n\nChoose any given option : " ;

                        cout << "\n\t 1. Insertion" ;

                        cout << "\n\t 2. Deletion" ;

                        cout << "\n\nEnter your choice :\t" ;

                        cin >> ch1;

                        switch (ch1)

                        {

                        case 1: obj.ins();

                                                              break;

                        case 2: obj.del();

                                                              break;

                        default: cout << "\n\nInvalid choice" ;

                        }

                        cout << "\n\nDo you want to continue? (y/n) :\t" ;

                        fflush(stdin);

                        cin >> ch2;

            }

            while (ch2=='y');

            obj.display();

            getch();

}