how to add together all doubles in a while loop, java

Question

while (read.hasNext()) {

String roomType = read.nextLine();
int rooms = read.nextInt();
double price = read.nextDouble();
double roomIncome = (double) (rooms*price);
double tax = (double) (price*rooms*defaultTax);
double totalIncome = roomIncome;
roomIncome++; 
read.skip("\\s+");      



        
System.out.println("Room type: " + roomType + " | No. of rooms: " + rooms + " | Room price: " + price + " | income: " + roomIncome + " | tax: " + tax);

System.out.println("The total room income is: " + totalIncome);

I need to add together all the roomIncome's together to give a totalIncome output. Currently my output is:

Room type: Single | No. of rooms: 5 | Room price: 23.5 | income: 118.5 | tax: 23.5
The total room income is: 117.5
Room type: Double | No. of rooms: 3 | Room price: 27.5 | income: 83.5 | tax: 16.5
The total room income is: 82.5
Room type: Suite | No. of rooms: 2 | Room price: 50.0 | income: 101.0 | tax: 20.0
The total room income is: 100.0

my expected output should be the total of all roomIncome added together. So in this case it should add up to 300. Instead it has added 1 to roomIncome and given me an output of 100

Answer 1

If you want to print total income for all rooms types combined, you need to maintain variable outside the loop and keep on adding values inside the loop, as below:

double allRoomsTotalIncome = 0.0;

while (read.hasNext()) {

  String roomType = read.nextLine();
  int rooms = read.nextInt();
  double price = read.nextDouble();
  double roomIncome = (double) (rooms*price);
  double tax = (double) (price*rooms*defaultTax);
  double totalIncome = roomIncome;
  allRoomsTotalIncome = allRoomsTotalIncome + totalIncome;
  roomIncome++; 
  read.skip("\\s+");      
        
  System.out.println("Room type: " + roomType + " | No. of rooms: " + rooms + " | Room price: " + price + " | income: " + roomIncome + " | tax: " + tax);
}



System.out.println("The total room income is: " + allRoomsTotalIncome);