Question

I’ve set up a “menu” that prints to console. Takes user input, calls according method, and then should return to the menu for further instruction. How should I structure my code so that it outputs the “menu” after it’s done doing whatever it’s doing?

public static void main(String[] args)throws Exception {
    // TODO Auto-generated method stub
    Scanner keyboard = new Scanner(System.in);
    EntryNode n = new EntryNode();
    AddressList addressBook = new AddressList();

    String menu = " ";

    System.out.println("******************************************************************");
    System.out.println("Welcome to the Jackie 2000 Address Book");
    System.out.println("What do you want to do? ");
    System.out.println("[p] View All Entries in Address Book  [a] Add New Entry");
    System.out.println("[d] Remove An Entry                   [s] Search for Entry");
    System.out.println("[i] Import Address Book               [x] Export Address Book");
    System.out.println("[z] Exit");

    System.out.println();
    System.out.println("Please enter your choice: ");
    menu = keyboard.next().toLowerCase();

    if (menu.equals("p")) {
        try {
            addressBook.printList();
        }
        catch (Exception e){

        }
    }
    else if (menu.equals("a")) {
        System.out.println("Enter in the first name ");
        String firstName = keyboard.next().toUpperCase();
        System.out.println("Enter in the last name ");
        String lastName = keyboard.next().toUpperCase();
        System.out.println("Enter in the phone number");
        String phoneNum = keyboard.next().toUpperCase();
        System.out.println("Enter in the email");
        String email = keyboard.next().toUpperCase();
        addressBook.addEntry(firstName,lastName,phoneNum,email);
    }
    else if (menu.equals("d")) {
        EntryNode temp = head;
        for (int i = 0; i <addressBook.length(); i++) {
            System.out.println(i + " Name: " + temp.getFirstName() + " " + temp.getLastName() + " " 
        + temp.getPhoneNum() + " " + temp.getEmail());
            temp = temp.getNext();
        }
        System.out.println(" ");
        System.out.println("Please enter the index of the entry you wish to delete ");
        int index = keyboard.nextInt();
        addressBook.removeEntry(index);
    }

    else if (menu.equals("s")) {
        System.out.println("Do you want to search by email or name? ");
        String decision = keyboard.next();
        if (decision.equals("email")) {
            System.out.println("What email address are you looking for? ");
            String email = keyboard.next();
            addressBook.searchEmail(email);
        }
        else if (decision.equals("name")) {
            System.out.println("What name are you looking for?");
            String name = keyboard.next();
            addressBook.searchEntry(name);
        }
        else System.out.println("Invalid entry. Type in 'email' or 'name'");
    }

    else if (menu.equals("i")) {
        addressBook.importBook();
    }

    else if (menu.equals("x")) {
        addressBook.exportBook();
    }

    else if (menu.equals("e")) {
        System.exit(0);
    }
    else {
        System.out.println("Invalid Entry");
    }
}

}

Answer 1

You should definitely take a look at java’s switch statement: http://docs.oracle.com/javase/tutorial/java/nutsandbolts/switch.html

You could have the entire switch-case statement inside a while loop with a boolean for when it should exit. For example:

while(!exit){
    switch(input){
         case "a": do something;break;
         case "d":...
         ...
         case "e": exit = true;
    }
}