i am failing to understand my source code .It can't be executed.i have spent a lot of time on this. I am using Visual..here is my source code. #include <iostream> #include <string> using namespace std; //class TRAVEL CONTROLS ALL FUNCTIONS class Travel { struct Hotel { string cityName; string hotelName; int hotelCode; int standardRoomNo; int standardRoomPrice; int deluxeRoomNo; int deluxeRoomPrice; }H; struct Resort { string cityName; int resortID; string resortName; int numberOfResorts; int resortPrice; }R; struct Booking { int reservationNum; string clientName; int contactTel; string email; char option; }B; public: void Hotelinput(); void Resortinput(); void Bookinginput(); void Display1(); void Display2(); void Display3(); } P; //********************************************************** // FUNCTION NAME : Hotel //********************************************************** void Travel::Hotelinput() { //DATA OF HOTEL cout<<"Enter Hotel Information:"; cout<<"Enter City Name:"; cin>>(H.cityName); cout<<"Hotel Name:"; cin>>(H.hotelName); cout<<"Hotel Code:"; cin>>(H.hotelCode); cout<<"Standard Room Number:"; cin>>(H.standardRoomNo); cout<<"Standard Room Price:"; cin>>(H.standardRoomPrice); cout<<"Deluxe Room Number:"; cin>>(H.deluxeRoomNo); cout<<"Deluxe Room Price:"; cin>>(H.deluxeRoomPrice); } void Travel::Resortinput() //DATA OFRESORT { cout<<"Enter City Name:"; cin>>(R.cityName); cout<<"Enter Resort ID:"; cin>>(R.resortID); cout<<"Enter Resort Name:"; cin>>(R.resortName); cout<<"Number Of Resorts:"; cin>>(R.numberOfResorts); cout<<"Enter Resort Price:"; cin>>(R.resortPrice); } void Travel::Bookinginput() //BOOKING DATA { cout<<"Enter Reservation Number:"; cin>>(B.reservationNum); cout<<"Enter Client Name:"; cin>>(B.clientName); cout<<"Enter Contact Tel.:"; cin>>(B.contactTel); cout<<"Enter E-mail:"; cin>>(B.email); cout<<"Enter Catergory(H for Hotel,R forResort):"; cin>>(B.option); } void Travel:isplay1() { cout<<"Hotel information:"; cout<<"City Name:"<<H.cityName<<endl; cout<<"Hotel Name:"<<H.hotelName<<endl; cout<<"Hotel Code:"<<H.hotelCode<<endl; cout<<"Standard Room Number:"<<H.standardRoomNo<<endl; cout<<"Standard Room Price:"<<H.standardRoomPrice<<endl; cout<<" Deluxe Room Number:"<<H.deluxeRoomNo<<endl; cout<<"Deluxe Room Price:"<<H.deluxeRoomPrice<<endl; } void Travel:isplay2() { cout<<"Resort information:"<<endl; cout<<"City Name:"<<R.cityName<<endl; cout<<"Resort Name:"<<R.resortName<<endl; cout<<"Resort ID:"<<R.resortID<<endl; cout<<"Resort Price:"<<R.resortPrice<<endl; } void Travel:isplay3() { cout<<"Reservation Number:"<<B.reservationNum<<endl; cout<<"Client Name:"<<B.clientName<<endl; cout<<"Contact Tel.:"<<B.contactTel<<endl; cout<<"E-mail:"<<B.email<<endl; cout<<"Catergory:"<<B.option<<endl; } int main() { void displayMain(); return 0; } void displayMain() { {int selection; do { cout<<"**********MAIN**********"<<endl; cout<<"1.) Add Hotel Information: " << endl; cout<<"2.) Add Resort Information:" << endl; cout<<"3.) Add New Booking:" << endl; cout<<"4.) View Hotel Information:"<<endl; cout<<"5.) View Resort Information:"<<endl; cout<<"6.) View Booking Information:"<<endl; cout<<"7.) EXIT" << endl; cout << "Selection: "; cin >> selection; } while (selection <= 0 && selection >= 7); switch (selection) { case 1: P.Hotelinput(); break; case 2: P.Resortinput(); break; case 3: P.Bookinginput(); break; case 4: P.Display1(); case 5: P.Display2(); case 6: P.Display3(); case 7://leave blank default: ; } } }