CODEWITHSUNDEEP
javarecursionstackcallstackcode-organization
nullByteMe
nullByteMe

Reputation: 6391

How to avoid stack build up?

I'm trying to figure out how I can write this method to avoid the stack buildup from recursively calling the method in the exception?

Here is the wording of my instructions:

Read a number, use an exception handler to make sure it is an int number and then add to the ArrayList object, aryList.

Here is my attempt:

public void createOriginalAryList() {

      Scanner keyboard = new Scanner(System.in);

      System.out.println("Enter a number: ");

      try {

         int number = keyboard.nextInt();
         aryList.add(number);

         while(keyboard.hasNextInt()) {

            System.out.println("Enter a number: ");
            number = keyboard.nextInt();
            aryList.add(number);

         }

      } catch(InputMismatchException ime) {
         System.out.println("Invalid number submitted! Try again.");
         createOriginalAryList();
      }

      System.out.println(aryList);
   }

Any suggestions are greatly appreciated!

Upvotes: 2

Views: 45

Answers (1)

willeM_ Van Onsem
willeM_ Van Onsem

Reputation: 477160

Simply use a do-while loop:

Scanner keyboard = new Scanner(System.in);

boolean redo = false;
do {
    System.out.println("Enter a number: ");
    redo = false;
    try {
       int number = keyboard.nextInt();
       aryList.add(number);

       while(keyboard.hasNextInt()) {

          System.out.println("Enter a number: ");
          number = keyboard.nextInt();
          aryList.add(number);

       }

    } catch(InputMismatchException ime) {
       redo = true;
       System.out.println("Invalid number submitted! Try again.");
    }
}
while(redo);
System.out.println(aryList);

Since initializing the Scanner keyboard each time is useless, it is put before the loop.

Upvotes: 2

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