java - 具有 3 个条件的 do-while 循环

Question

我陷入了 do-while 循环，它需要循环 do-while 直到用户输入三个正确字符串之一

我试过了

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();
}

使用该语法，它仅检索 (vehicleCondition.equals(motor)。我的预期结果是它可以检索 (vehicleCondition.equals(motor), (vehicleCondition.equals(mobil), (vehicleCondition.equals(kosong)).

Answer 1

如果您删除多余的括号，可能更容易发现您有 while (!a || b || c) 而不是 while (!(a || b | | c)).

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

或者，等效地通过 De Morgan's laws , while (!a && !b && !c):

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