Help This Beginner

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:
;
}
}
}