CODEWITHSUNDEEP
javawhile-loopdo-while
Ferial Adrian
Ferial Adrian

Reputation: 83

do-while loopwith 3 conditions

I'm in a stuck with do-while looping that requires looping with do-while until users input one of three correct strings

I've tried with this

Scanner input = new Scanner(System.in);
    String motor = "motor";
    String mobil = "mobil";
    String kosong = "";
    String baru = "baru";
    int tahun = Calendar.getInstance().get(Calendar.YEAR);

do {
        inputVehicleType();
        vehicleCondition = input.next();
    }
while (!(vehicleCondition.equals(motor)) || (vehicleCondition.equals(mobil)) || (vehicleCondition.equals(kosong)));

System.out.println("SUCCED");

private static void inputVehicleType() {
    System.out.println(Constant.HEADER);
    System.out.println("Input Jenis Kendaraan Mobil/Motor --> (jenis [motor/mobil])");
    titleFooter();
}

with that syntax it only retrieve (vehicleCondition.equals(motor). My expected result was it can retrieve (vehicleCondition.equals(motor), (vehicleCondition.equals(mobil), (vehicleCondition.equals(kosong).

Upvotes: 1

Views: 128

Answers (5)

Bentaye
Bentaye

Reputation: 9766

Make a method to check the condition:

private static boolean isValidVehiculeCondition(String vc) {
    return !Arrays.asList("motor", "mobil", "baru").contains(vc.toLowerCase());
}

Then loop while it returns true (ie: input is not valid)

do {
    inputVehicleType();
} while(isNotValidVehiculeCondition(input.next()));

Upvotes: 0

amitkhonde
amitkhonde

Reputation: 1

I think you have a little parenthesis mistake in your code. You need to add an extra parenthesis around not operator. Your condition should be

while (!(
  (vehicleCondition.equals(motor)) ||
  (vehicleCondition.equals(mobil)) || (vehicleCondition.equals(kosong))
));

Upvotes: 0

PrzemyslawP
PrzemyslawP

Reputation: 340

You have made a mistake in your while logic expression

should be:

while (!((vehicleCondition.equals(motor)) || (vehicleCondition.equals(mobil)) || (vehicleCondition.equals(kosong))));

Upvotes: 3

John Kugelman
John Kugelman

Reputation: 361849

If you remove the excess parentheses it may be easier to spot that you have while (!a || b || c) instead of while (!(a || b || c)).

do {
    ...
} while (!(vehicleCondition.equals(motor) ||
           vehicleCondition.equals(mobil) ||
           vehicleCondition.equals(kosong)));

Or, equivalently via De Morgan's laws, while (!a && !b && !c):

do {
    ...
} while (!vehicleCondition.equals(motor) &&
         !vehicleCondition.equals(mobil) &&
         !vehicleCondition.equals(kosong));

Upvotes: 5

Eran
Eran

Reputation: 393936

The correct condition would be:

while (!(vehicleCondition.equals(motor) || 
         vehicleCondition.equals(mobil) || 
         vehicleCondition.equals(kosong)));

i.e. you should stay in the loop as long as vehicleCondition is not equal to one of the 3 expected values.

Upvotes: 1

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