I can't seem to work a way for my recommend program to track "Invalid Answers"

Question

Here is the code:

do {
    System.out.println("Question #1:");

    System.out.println("What is your budget for purchasing the laptop?");

    System.out.println("A. >$500.00");
    System.out.println("B. $500.00 - $700.00");
    System.out.println("C. $700.00 - $1000.00");
    System.out.println("D. <$1000.00");
    questionArray [0] = myScanner.nextLine();
    if (!questionArray [0].equals ("A") || !questionArray [0].equals ("B") || !questionArray [0].equals ("C") || !questionArray [0].equals ("D")) {
      System.out.println("Invalid Entry");
    }
} while (!questionArray [0].equals ("A") || !questionArray [0].equals ("B") || !questionArray [0].equals ("C") || !!questionArray [0].equals ("D"));

Basically, even when I write a valid response (eg. "A") it still counts it as an invalid answer, and restarts the question. Any help would be greatly appreciated! :)

Answer 1

When the condition gets complex, it is a good idea to try and simplify the complexity by using variables to make code cleaner and easier to understand. For example:

    boolean validCondition = false;

    do {
        System.out.println("Question #1:");
        System.out.println("What is your budget for purchasing the laptop?");

        System.out.println("A. >$500.00");
        System.out.println("B. $500.00 - $700.00");
        System.out.println("C. $700.00 - $1000.00");
        System.out.println("D. <$1000.00");

        questionArray[0] = myScanner.nextLine();

        validCondition = questionArray[0].equals("A") || questionArray[0].equals("B") || questionArray[0].equals("C")
                || questionArray[0].equals("D");

        if (!validCondition) {
            System.out.println("Invalid Entry");
        }
    } while (!validCondition);