Thread: Missing Loop, not sure what I need

import java.util.Scanner;
public class Apartment 
{
public static void main(String[] args)
{
	int unit, rent, main, increase, min=0, ntotal=0, total=0, profit, irent=0;
	int nunit=0, ncost, cost, max;
	Scanner keyboard = new Scanner(System.in);
 
	System.out.println("Enter the total number of apartment units:");
	unit=keyboard.nextInt();
	System.out.println("Enter the rent to occupy ALL the units:");
	rent=keyboard.nextInt();
	System.out.println("Enter the increase in rent that results in a vacant unit:");
	increase=keyboard.nextInt();
	System.out.println("Enter the amount to maintain a rented unit:");
	main=keyboard.nextInt();
 
	 total=(rent*unit);
	 cost=unit*main;
     profit=total-cost;
 
 do 
  {
	  nunit=(unit-1);
	  irent=(increase+rent);
	  ntotal=(irent*nunit);
	  ncost=nunit*main;
	  min=ntotal-ncost;
  } 
while (profit>min);
 
 
 
 
 
	System.out.println("With "+unit+" apartment units and $"+rent+" each to occupy ALL the units, ");
	System.out.println("assuming that each increase of $"+increase+" results in one vacant unit, and");
	System.out.println("assuming that it costs $"+main+" to maintain each unit ...");
 
	System.out.println("The optimum rent to charge is "+irent);
	System.out.println(nunit+" apartment units can be rented at this rate.");
	System.out.println("This will yield a total of "+min+" per month.");
 
	System.exit(0);
}
}

I am trying to figure out what my other loop should be. I need the program to run and find max amount of profit. i think i need to add a for loop, but I am not sure.

Sorry for the vague description on what I am trying to do. an example of what I am trying to do is, take 50 apartments with $600 rent. The maintenance for an occupied apartment is $27. For every empty apartment the rent goes up $40. i am trying to get my program to tell me what is the least amount of apartments that can be rented for the maximum amount of profit. I had to use System.exit(0), because the program kept running. once I get it set the right way I will take it out, for I agree it will not be needed. I will change the variable main to maintenance, to make the program read better. thank you for the input.

So it sounds like I was going at it backwards. I need to start the apartments at 1 and increase until I find the max profit. I will turn it around and see if I can get it to run. THANK YOU!!!!!!!