how to loop in switch case
do {
menu_selection = main_menu();
switch (menu_selection) {
case 1 : display(primes); break;
case 2 : display(fibos); break;
case 3 : display(primes_and_fibos); break;
case 4 : display(primes_not_fibos); break;
case 5 : display(fibos_not_primes); break;
case 6 : search(); break;
case 7 : break;
default: cout << "\nThat is an invalid option. Please try again.\n\n";
} while (condition_main != 7);
return 0;