سوال: نوشتن case 4 برنامه با تابع

سلام دوستان این یک برنامه مدیریت کتاب هست
که کیس 4 قرار یک مولف رو بگیره و کتاب های ان رو نمایش بده
تابع شو نوشتم ولی یک ایدی میگیره و اطلاعات رو نمایش میده
اما من میخوام یک مولف رو بگیره و اطلاعات رو نمایش بده ممنون میشم کمکم کنید

#include <iostream.h>

#include <conio.h>

#define size 100



struct node

{

    int id;

    char moalef[30];

    int mojodi;

    

    node *next;

};



node *back, *start = NULL;









node *find_book(int id)

{

    node *t, *b;

    t = start;

    b = NULL;

    while (t != NULL)

    {

	if (t -> id==id)

            break;

        b = t;

        t = t -> next;

    }

    if (t == NULL)

        cout << " not found.\n";

    else

        back = b;

    return t;

}



void delete_book(int id)

{

    node *t;

    t = find_book(id);

    if (t == NULL)

        return;

    if (back == NULL)

        start = t -> next;

    else

        back -> next = t -> next;

    delete t;

}





int main()

{

    clrscr();

    node *t, *p, *z;

    int a;

    int b;

    do

    {

	cout<<"__________________________________________\  n";

	cout << "\n1->Rejistr BOOK \n";

	cout << "2->Show All Data (ISBN)  \n";

	cout << "3->ENTER ISB \n";

	cout << "4->search  (MOlef) \n" ;

	cout << "5->Delete \n";

	cout << "6->yek adad dariaft \n\n";

        cout << "7->EXIT \n\n";



	cout<<"_________________________________________\n  ";

	cout<<"\n";



	cout << "Enter 1,2,3,4,5,6,7 :\n";

        cin >> a;

	switch(a)

        {

            case 1:

                t = new node[1];

		cout << "Enter ID :\n ";

		cout<<"\n";

		cin >> t->id;

		cout<<"\n";

		cout << "Enter Moalef :\n ";

		cout<<"\n";

		cin >> t -> moalef;

		 cout<<"\n";

		cout << "Enter mojodi:\n ";

		cout<<"\n";

		cin >> t -> mojodi;

		   cout<<"\n";

		cout << "Submit Data\n";

		cout<<"\n";

			cout<"--------------------\n";

			 cout<<"\n";

		z = start;

		p = NULL;

                while (z != NULL && z -> id < b)

                {

                    p = z;

                    z = z -> next;

                }

                if (p == NULL)

                {

                    t -> next = start;

                    start = t;

                }

                else

                {

                    t -> next = p -> next;

                    p -> next = t;

                }

                break;

            case 2:

                if (start == NULL)

                    cout << "List is empty.\n";

                p = start;

                while (p != NULL)

                {

                    cout << "ID = " << p -> id << "    Moalef= " << p -> moalef

                    << "    Mojodi= " << p -> mojodi<< "\n";

                    p = p -> next;

                }

		break;

	    case 3:

		cout << "enter id :\n ";

		cin >> b;

		p = find_book(b);

		if (p != NULL)

		    cout << "ID = " << p -> id << "    moalef= " << p -> moalef

		    << "    mojodi= " << p -> mojodi<< "\n";

		break;



	    case 4:

		cout << "enter id :\n ";

		cin >> b;

		p = find_book(b);

		if (p != NULL)

		    cout << "ID = " << p -> id << "    moalef= " << p -> moalef

		    << "    mojodi= " << p -> mojodi<< "\n";

		break;

            case 5:

                cout << "enter ID :\n ";

                cin >> b;

		delete_book(b);

		cout<<"Delete ="<<b<<"\n";

                break;

	}

    } while (a != 7);

    cout<<"END Program";

    getch();

    return 0;

}