I'm having a little trouble with this code. I've been assigned to make an Airline Reservations System script. Here's what I have to do:

There's a 10 element array, and that represents the seating chart on the plane. All elements are set to 0. When a person takes a seat, that element is substituted with a 1 to declare that the seat has been filled. There are two seating sections: First Class and Economy. A person can decide what section they want their seat in. If First Class has been completely filled, then the program asks if it should assign a seat to the Economy. If yes, then a seat in Economy gets filled. If no, a message is displayed.

Here's what I have so far:

Code:
#include <iostream.h>
#include <windows.h>

int main (int argc, char *argv[])
{
	// Define the input values
	string economy_input;
	int input;
	int counter = 0;
	

	// Define the arrays
	int firstclass[5] = {0, 0, 0, 0, 0};
	int economy[5]	 = {0, 0, 0, 0, 0};

	while (counter != -1)
	{
		for (int i = 0; i < sizeof(firstclass); i++)
		{
		cout << "Please type in 1 for \"First Class\" or 2 for \"Economy\"" << endl;
		cin >> input;

		if (input == 1) // "First Class" has been entered
		{
			if (firstclass[i] == 0 && firstclass[i] <= sizeof(firstclass)) // Checks to make sure that there is a spot left in the array
			{
				firstclass[i] = 1; // Fill in the element
				cout << "Assigning the person's seat to: " << i << " in the first class section." << endl;
			}
			else
			{
				cout << "All of the first class spaces have been filled. Would you like to go to economy? Yes or No" << endl;
				getline(cin,economy_input);

				if (economy_input == "No")
				{
					cout << "Next flight leaves in 3 hours." << endl;
				}
				if (economy_input == "Yes")
				{
					if (economy[i] == 0 && economy[i] <= sizeof(economy))
					{
						economy[i] = 1;
						cout << "Assigning the person's seat to: " << i << endl;
					}
				}
			}
		}

		
		if (input == 2) // "Economy" has been entered
		{
			for (int i = 0; i < sizeof(economy); i++)
			{
			if (economy[i] == 0 && economy[i] <= sizeof(economy))
			{
				economy[i] = 1;
				cout << "Assigning the person's seat to: " << i << " in the economy section." << endl;
			}
			}
		}
	}

	return 0;
}
I'm not sure how the for loops and while loop would work for this script. I don't even know if there are suppose to be for loops/while loops. If someone could help me fix this up, it would be much appreciated.