function not working when called.

Please post code calling this function with the true condition.

The problem more then likely is that you're really not getting a true condition.

Try putting a break point on the if condition, and then examin the variable values to verify their condition.

you can put a

cout << businessEntries << economyEntires;

before the if ()

Axter,
This is one of the functions that uses checkEmpty.

void cancelBooking(string name[], long phoneNo[],string seatClass[],
                       int& businessEntries,int& economyEntries)
{
     if (checkEmpty(businessEntries, economyEntries)) return;
     
     cout<<"Please enter the name to be cancelled: ";
     cin>>ws;
     string toDelete = getValidName();
     
     // find the booking in the reservations system
     int index =-1;
     index = seqSearch(name,toDelete, businessEntries, economyEntries);
     if(index == -1)
     {
          cout<< toDelete << " is not in the booking list.\n"<<endl;
          return;
     }
     
     cout<< toDelete << " booking cancelled.\n"<<endl;
     // blank out the deleted name
     name[index] = "";
}
if there have been no bookings entered at all it doesn't say "The Reservations are empty"........

It does however, search for any name you enter and return the result.

Axter,
I have run the debug putting a breakpoint on the if statement.  It seems the variables have a value of businessEntries=1 and economyEntries=9.  Am I right to assume that it's picking up initialized values from the main function?
int main(void)
{      
    string name[MAX_ENTRIES] = {" "}, seatClass[MAX_ENTRIES]={" "} ;
      long phoneNo[MAX_ENTRIES] = {0};
      int  businessEntries = 0, economyEntries = 3 * 3; // Economy skips the first 3 rows and 3 columns

and if so does that mean I have to somehow initialize the variables within the checkEmpty function?

Another tiny suggestion...

cout << "The reservations are empty" << endl;

You've ended the string with a \n, which would print the line if you were using printf(), but it isn't guaranteed to do the same thing using C++ I/O. You could be getting the message but not seeing it because the stream buffer wasn't flushed to the output.

I've seem implementations that work both ways. std::endl will definitely flush the buffer.

Thanks all for the help.  :)