Can't figure out why is ArrayList of objects not sorted properly

Question

I'm working on an exchange sort for an ArrayList of objects so that it can be sorted ascending depending on the value in the object. When I compile it, everything works great until the last element is not sorted properly. I suspect that the problem is with the iterator. I tried many combinations but it won't sort properly. Also, I can't use sort() or any prebuilt libraries. I'd appreciate any guidance!

void sortAndDisplay (ArrayList<Car> cars) {

    Car temp;

    for (int i = 0; i < cars.size() -1; i++) {
        for (int j = i+1; j < cars.size(); j++ ) {
            if (((cars.get(i).getMake()).compareToIgnoreCase(cars.get(j).getMake()) > 0)) {
                temp = cars.get(i);
                cars.set(i, cars.get(j));
                cars.set(j, temp);
            }


        }
    }


      for (int i = 0; i < cars.size(); i++) { 
          System.out.print(cars.get(i)+"\n\n");

      }


}

The Car class:

public class Car {
String make;
String model;


public Car (String make,
            String model)   {

    this.make = make;
    this.model = model;

}

public String getMake() {
    return make;

}

The method I used to read the values from the file:

ArrayList<Car> readCars(FileReader file) throws Exception  {
    String arr[] = {};
    String line = "";
    BufferedReader scan = new BufferedReader(file);
    ArrayList<Car> carsArr = new ArrayList<Car>();

    while ((line = scan.readLine()) != null) {
        arr = line.split(","); 
        Car car = new Car(arr[0], arr[1]);
        carsArr.add(car);
    }
    System.out.println("The file was read.");
    return carsArr;

}

Answer 1

java has sorting built in:

void sortAndDisplay (List<Car> cars) {
    cars.sort(Comparator.comparing(Car::getMake));
    System.out.println(cars.stream().collect(Collectors.joining("\n\n")));
}

Answer 2

I created the file x.txt with the following data:

WERTfgd, bmw
ETRHFDdfgsdf, bmw
ewrd, bmw
HTfgdfgs, bmw
dDSFSfgd, bmw
ter, bmw
jhvbn, bmw
Frqw, bmw

I copied your code literally by adding getMake() into this System.out.print (cars.get (i).getMake () + "\ n \ n");in order to get the wanted output...

Output

dDSFSfgd

ETRHFDdfgsdf

ewrd

Frqw

HTfgdfgs

jhvbn

ter

WERTfgd

Which is correct, so I can't figure out what's your problem.

Maybe you are not sure how the method compareToIgnoreCase() works?

Answer 3

Tried your code with short example list and it worked. Could you give a failing example input with corresponding output?

BTW I recommend adding a toString() method to the Car class. For example:

@Override
public String toString() {
    return "<Car<" + make + "><" + model + ">>";
}

With that printing the list of cars can be done like:

System.out.println(cars);