I need help.

How do I display the id number that I input to case 2?

Code:

#include <iostream.h> 
#include <windows.h>
#include <stdlib.h>


int studentID( int n[], int maxStudent);
int regID;






int main()
{
    int mainMenu;
    int studentlist;
    int Exams;
    int Reports;
    
    
    
    system ("COLOR 3F");






    cout << "\t\t\tWelcome to Student Record Program"<<endl<<endl<<endl;
    cout << "\t\tM A I N  M E N U\n";
    cout << "\t\t_____________________________________"<<endl;
    cout << "\t\t(1) - STUDENT LIST " <<endl;
    cout << "\t\t(2) - EXAMS " <<endl;
    cout << "\t\t(3) - REPORTS " <<endl;
    cout << "\t\t(4) - EXIT FROM THE PROGRAM "<<endl;
    cout << "\t\t_____________________________________"<<endl<<endl;
    cout << "\t\tEnter here ===>> ";
    cin >> mainMenu;












switch(mainMenu)
    




{
// Students List Menu
    case 1:
        {
            


            system("cls");
            cout <<endl<<endl;
            cout <<"\t\tS T U D E N T   L I S T   M E N U "<<endl;
            cout <<"\t\t___________________________________"<<endl;
            cout <<"\t\t(1) - Add a student ID number. " <<endl<<endl;
            cout <<"\t\t(2) - Delete a student Record. " <<endl<<endl;
            cout <<"\t\t(3) - Back to Main Menu. "<<endl;
            cout <<"\t\t___________________________________"<<endl<<endl;
            cout <<"\t\t\tEnter here ==>> ";
            cin >>studentlist;




        switch(studentlist)
        {    
        case 1:
            {
            
                
                int maxStudent;
                int n[40];
            
                
            




                system("cls");
                cout <<"\t\t\tHow many students you want to add?"<<endl;
                cout <<"\t\t\t\tEnter here ==> ";
                cin >>maxStudent;
                for(int i=0;i<maxStudent;i++)
                {
                    system("cls");
                    cout<<endl<<endl;
                    cout<<"\tEnter the student ID number of student "<<i+1<<endl;
                    cout<<"\tEnter here: ";
                    cin>>n[i];
                    {
                        system ("cls");
                        cout <<endl<<endl<<endl;
                        cout << "\t\t\tThe new student has been added."<<endl;
                        system ("pause");
                    }
                    
                    system ("cls");
                    
                }
                
                






                return main();
            }


            return 0;
            break;
        case 2:
            
            { 
                cout <<regID;
                
                








            








            }
            
            
            
            












            return 0;
            break;
        case 3:
            system("cls");
            return main();
            break;
        }
        
        return 0;
        }


// EXAMS Menu
    case 2:
        {
            system("cls");
            cout <<endl<<endl;
            cout <<"\t\tE X A M    M E N U "<<endl;
            cout <<"\t\t___________________________________"<<endl;
            cout <<"\t\t(1) - Set Number of Quiz. " <<endl;
            cout <<"\t\t(2) - Input Scores For Certain Quiz. " <<endl;
            cout <<"\t\t(3) - Back to Main Menu. "<<endl;
            cout <<"\t\t___________________________________"<<endl;
            cout <<"\t\t\tEnter here ==>> ";
            cin >>Exams;
            
        switch(Exams)
        {
        case 1:
            return 0;
            break;
        case 2:
            return 0;
            break;
        case 3:
            system("cls");
            return main();
            break;
        }
        return 0;
        }




// Reports Menu
    case 3:
        {
            system("cls");
            cout <<endl<<endl;
            cout <<"\t\tR E P O R T    M E N U "<<endl;
            cout <<"\t___________________________________"<<endl;
            cout <<"\t(1) - Compute for Average. " <<endl;
            cout <<"\t(2) - Display the whole grading sheet. " <<endl;
            cout <<"\t(3) - Display The student list and average grades in ascending order. "<<endl;
            cout <<"\t(4) - Back to main menu."<<endl;
            cout <<"\t___________________________________"<<endl;
            cout <<"\t\t\tEnter here ==>> ";
            cin >>Reports;


        switch(Reports)
        {
        case 1:
            return 0;
            break;
        case 2:
            return 0;
            break;
        case 3:
            return 0;
            break;
        case 4:
            system("cls");
            return main();
            break;
        }
        return 0;
        }


    // EXIT 
    case 4:
        {
            system("cls");
            cout << "\t\t\tThank you for using my program."<<endl<<endl<<endl;
        
    
        return 0;
        }




        return 0;
    }
    


    














    return 0;
}


int studentID( int n[], int maxStudent )
    {
        int regID=0;
    for (int i=0; i<maxStudent;i++)
    {
        regID=n[i];
        cout << "input id number: ";
        cin >> n[i];
    
    }
    return regID;
    
    }

"We are not allowed to use Structures and Multidimensional Array"

You're not using the studentID function