Array validation through a while loop

Question

I am doing "Rock,Paper,Scissors" game and I want to check if the input matches with any arrays, for now I have this code and it works perfect:

String[] rockArray = {"Rock","rock","1"},
         paperArray = {"Paper","paper","2"},
         scissorsArray = {"Scissors","scissors","3"};
String[][] answersArray = {rockArray, paperArray, scissorsArray};

//Scanner
Scanner scan = new Scanner(System.in);

// Input
System.out.print("\nRock, Paper or Scissors? -> ");
String answer = scan.next();

 // Checking if the input contains the right values
 while(!Arrays.asList(answerRock).contains(answer) &&
       !Arrays.asList(answerPaper).contains(answer) &&
       !Arrays.asList(answerScissors).contains(answer)) {

         System.out.print("Try again: ");
         answer = scan.next();
 }

But I want to make it simple and here is my idea but for some reason it doesn't work:

// Here is my arrays 
String[] rockArray = {"Rock","rock","1"},
         paperArray = {"Paper","paper","2"},
         scissorsArray = {"Scissors","scissors","3"};
String[][] globalArray = {rockArray, paperArray, scissorsArray};

// Input
System.out.print("\nRock, Paper or Scissors? -> ");
String answer = scan.next();

//Validation
while(!Arrays.asList(globalArray).contains(answer) {
      System.out.println("Try again: ");
      answer = scan.next();
}

Thank you very much!

see stackoverflow.com/questions/80476/…

Scary Wombat
– Scary Wombat

2016-02-25 06:05:32 +00:00
Commented Feb 25, 2016 at 6:05 — Scary Wombat
– Scary Wombat, Commented Feb 25, 2016 at 6:05

MartinS · Accepted Answer · 2016-02-25 06:14:29Z

3

String[][] globalArray = {rockArray, paperArray, scissorsArray};
...
Arrays.asList(globalArray)

This call to Arrays.asList() will create list with 3 elements, the 3 array and not a list with the content of the arrays. When you then use contains to search for the element, you will always get false because answer will never be on of the arrays (how would it, it's a String not an array).

I suggest you do something like this:

List<String> allAnswers = Arrays.asList(rockArray);
allAnswers.addAll(Arrays.asList(paperArray));
allAnswers.addAll(Arrays.asList(scissorsArray));
...
while(!allAnswers.contains(answer)) {
  ...

This also saves you from calling Arrays.asList() over and over again which improves performance.

edited Feb 25, 2016 at 6:14

answered Feb 25, 2016 at 6:05

MartinS

2,8201 gold badge17 silver badges25 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Maljam · Accepted Answer · 2016-02-25 06:06:09Z

1

!Arrays.asList(globalArray).contains(answer) doesn't work because the Arrays.asList(...) method will output a List<String[]> not List<String>.

If you really want to use asList(...) you have to input an String[] allPossibleInputString

answered Feb 25, 2016 at 6:06

Maljam

6,2843 gold badges20 silver badges31 bronze badges

Comments

ninja.coder · Accepted Answer · 2016-02-25 06:21:37Z

0

Your second code snippet does not work because you can't do something like this !Arrays.asList(globalArray).contains(answer).

One solution is to copy the contents of the three array into your global array like this:

String[] rockArray = {"Rock","rock","1"},
         paperArray = {"Paper","paper","2"},
         scissorsArray = {"Scissors","scissors","3"};
String[] globalArray = new String[9];
/* Copy Contents To Global Array */
System.arraycopy(rockArray, 0, globalArray, 0, 3);
System.arraycopy(paperArray, 0, globalArray, 3, 3);
System.arraycopy(scissorsArray, 0, globalArray, 6, 3);

Now you can do this:

while(!Arrays.asList(globalArray).contains(answer)) {
    System.out.println("Try again: ");
    answer = scan.nextLine();
}

edited Feb 25, 2016 at 6:21

answered Feb 25, 2016 at 6:04

ninja.coder

9,6685 gold badges40 silver badges55 bronze badges

4 Comments

John E. Over a year ago

Right, that's why I am asking if there are any other ways to do it?

John E. Over a year ago

in this case, if I enter "test", I will get an infinite loop and it won't except the correct input

ninja.coder Over a year ago

That's because it should be scan.nextLine() and not just scan.next(). It works perfectly. Check here: ideone.com/kB4U3n

ninja.coder Over a year ago

@S.Anthony Your Welcome! :)

Collectives™ on Stack Overflow

Array validation through a while loop

3 Answers 3

Comments

Comments

4 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

4 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related