public class Test1 {
   public static void main(String[] args) {
      System.out.println("Give me a word: ");
      Scanner console = new Scanner(System.in);
      ArrayList<String> arr = new ArrayList<>();
      boolean found = true;
      
      while (console.hasNextLine() && found) {
         String line = console.nextLine();
         
         if (line.equals("")) {
            found = false;
         } else {
            arr.add(line);
         }
      }
     
      System.out.println("You said: ");
      
      for (int index = 0; index < arr.size(); index  ) {
         System.out.println(arr.get(index)); 
      } 
   }
}

I'd like to print what user typed in whenever the user types enter twice, however this requires three enters to be inputted for some reason. When I remove the console.hasNextLine statement in while loop's condition, it works perfectly fine. Why is this the case?

CodePudding user response：

console.hasNextLine() blocks application flow and waits for input to be received.

1st enter - word is found and found remains == true

2nd enter - word is not found and found is set to == false

3rd enter - is required because your booleans are evaluated in order which they are arranged. so first it'll call console.hasNextLine() and allow user to provide input. THEN it'll check if found == true/false which would == false and would break out of the loop.

an easy solution would be to rearrange your conditions to be

found  && console.hasNextLine()