help me to figure out the error pls........

[krishna florida]

#include<iostream.h>
char NAME[10];
int PH_NUM;
class customer
{
char namE[100];
int ph_number;
public: int add_cust()
{
cout << "enter ur customer" <<endl;
cin >> NAME;
cout << "enter the phone number" << endl;
cin >> PH_NUM;
cout << "ur details are entered " << NAME << PH_NUM << endl;
return 0;
}
public: int update_cust()
{
cout<< "enter ur name: " << endl;
cin >> namE;
cout << "enter ur phone_number: " << endl;
cin >> ph_number;
cout << "customer details has been changed:" << name << ph_number << endl;
return 0;
}
public: int view_cust()
{
cout << "The customer details are" << NAME << PH_NUM <<endl;
return 0;
}
};
void main()
{
int ch;
customer c;
label1: cout << "1.add details\n 2. update details\n 3.view details\n 4.go to back\n 5.exit \n" << endl;
cout << "Enter ur choice :" << endl;
cin >> ch;
switch(ch)
{
case 1: c.add_cust();
break;
case 2: c.update_cust();
break;
case 3: c.view_cust();
break;
case 4: goto label1;
case 5: exit(0);

}
}



ERROR :: function 'exit' should have a prototype..........

[vlad from moscow]

Include directive

#include <cstdlib>