Java字符串验证循环

Question

I have a quick question regarding Java. I'm currently studying for a coding assignment coming up regarding arrays. Essentially the assignment is making a few String arrays and randomly generating numbers to pick elements of the array.

One of the requirements of the assignment is to do validation, the String that is a result of picking from the two arrays. Our rules for validation is that the string can't be greater than 8 characters in length. If it's greater than 8 we need to randomly generate another string that is less than or equal to 8 characters.

I've tried using a do-while and a while(loopFlag) validation loop. But I just can't seem to get it to work properly. Typically what will happen is the console runs into an error and just gets stuck in the validation loop. I tried making an int characterLength and using the .length() method but it doesn't seem to work.

Any help would be greatly appreciated!

Thanks!

Answer 1

Random random = new Random();
String [] results = new String[50];
int index = 0;

while(index < results.length) {

    //to get some random values
    //String num = String.valueOf(someByteArray);
    String num = String.valueOf(random.nextInt()); //value from first array
    num += String.valueOf(random.nextInt()); //value from second array


    // to long?
    if(num.length() > 8) {
        System.out.println("Not valid " + num);
        continue;
    }

    try {
        //is it number?
        Integer.valueOf(num);
    } catch (NumberFormatException e) {
        //it was not number or to big for int
        System.out.println("Not valid " + num);
        continue;
    }

    results[index++] = num;
    System.out.println("Valid " + num);
}

Answer 2

It all ended up being the location of where i ended my do-while. My prof taught us that you should always validate your inputs before they are added to your arrays/variables.

I ended up using the do-while loop but included all of the code from the for loop instead of ending the do-while before I add the result to the array.

do { ...... }while(vanityPlate.length()<9);

Thanks for all the help guys!