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Thread: do-while loop containing switch statement cotinues looping when end statement is supposed to be reached?

  1. #1
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    Question do-while loop containing switch statement cotinues looping when end statement is supposed to be reached?

    Hello, I feel like I've tried everything and I genuinely don't know how to fix this. The point is for the program to accept both specific commands and 1-5 as acceptable inputs as the commands are pretty long to be typing in every time. Everything seems to work up until the point the do-while loop in the "runCommands" is supposed to end when "5" or "exit" is entered, but the loop just keeps on going. Does anyone have any idea how to solve this?


    Any help would be endlessly appreciated


    import java.util.Scanner;

    public class CodeAssignment {

    private Scanner input = new Scanner(System.in);

    private void newPrintln(String prompt) {
    System.out.println(prompt);
    }

    private void programMenu() {
    newPrintln("What would you like to do?"
    + "\n1. register new person. "
    + "\n2. increase age"
    + "\n3. list people"
    + "\n4. remove person"
    + "\n5. exit");
    }


    public void run() {
    initialize();
    runCommands();
    exitProgram();
    }


    private void initialize() {
    System.out.println("Welcome to the database!");
    programMenu();


    }


    private void runCommands() {
    String choice;
    do {
    System.out.println("> ");
    choice = interpretChoice();
    excecuteChoice(choice);

    } while (choice != "exit" && choice != "5");

    }


    private String interpretChoice() {
    String choice = input.nextLine();
    return choice;
    }


    private void excecuteChoice (String choice) {
    switch (choice) {
    case "1":
    case "register new person":
    break;

    case "2":
    case "increase age":
    break;

    case "3":
    case "list people":
    break;

    case "4":
    case "remove person":
    break;

    case "5":
    case "exit":
    break;
    default:
    newPrintln("Error: no such command."
    + "\nTry again!");
    programMenu();
    }
    }




    private void exitProgram() {
    newPrintln("Goodbye!");
    input.close();

    }
    Last edited by alyss; December 10th, 2019 at 06:15 AM.

  2. #2
    Super Moderator Norm's Avatar
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    Can you copy the contents of the command prompt window and paste it here so we can see what you are talking about?

    Where is the class's main method? It is needed for testing.

    Please edit your post and wrap your code with code tags:

    [code]
    **YOUR CODE GOES HERE**
    [/code]

    to get highlighting and preserve formatting.

    Note: Use the equals method for comparing the contents of String objects, not the == or != operators.
    If you don't understand my answer, don't ignore it, ask a question.

  3. The Following User Says Thank You to Norm For This Useful Post:

    alyss (December 10th, 2019)

  4. #3
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    Thumbs up Re: do-while loop containing switch statement cotinues looping when end statement is supposed to be reached?

    Thank you so much for replying, here's the code in hopefully correct format. (+ main method)

     
    import java.util.Scanner;
     
    public class CodeAssignment {
     
    private Scanner input = new Scanner(System.in);
     
    private void newPrintln(String prompt) {
    System.out.println(prompt);
    }
     
    private void programMenu() {
    newPrintln("What would you like to do?"
    + "\n1. register new person. "
    + "\n2. increase age"
    + "\n3. list people"
    + "\n4. remove person"
    + "\n5. exit");
    }
     
     
    public void run() {
    initialize();
    runCommands();
    exitProgram();
    }
     
     
    private void initialize() {
    System.out.println("Welcome to the database!");
    programMenu();
     
     
    }
     
     
    private void runCommands() {
    String choice;
    do {
    System.out.println("> ");
    choice = interpretChoice();
    excecuteChoice(choice);
     
    } while (choice != "exit" && choice != "5");
     
    }
     
     
    private String interpretChoice() {
    String choice = input.nextLine();
    return choice;
    }
     
     
    private void excecuteChoice (String choice) {
    switch (choice) {
    case "1":
    case "register new person":
    break;
     
    case "2":
    case "increase age":
    break;
     
    case "3":
    case "list people":
    break;
     
    case "4":
    case "remove person":
    break;
     
    case "5":
    case "exit":
    break;
    default:
    newPrintln("Error: no such command."
    + "\nTry again!");
    programMenu();
    }
    }
     
     
     
     
    private void exitProgram() {
    newPrintln("Goodbye!");
    input.close();
     
    }
     
     
    public static void main(String[] args) {
     
    		CodeAssignment program = new CodeAssignment();
    		program.run();
     
     
    	}
     
    }


    Here are the contents of the command window:

    Welcome!
    What would you like to do?
    1. register new person.
    2. increase age
    3. list people
    4. remove person
    5. exit
    >
    1
    >
    2
    >
    3
    >
    4
    >
    5
    >
    exit
    >

    Even after 5 or "exit" is entered the loop just keeps on going.
    (Haven't done methods for the other alternatives yet, which is why everything is blank)

    --- Update ---

    update, solved it! Thank you for mentioning the string.equals, I'd forgotten about that

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