Not sure if I got the conditions right.

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Hello everyone, my program does precisely what the conditions are stated, but the Judge has a different opinion, pls gimme a hint.

package en.codegym.task.pro.task04.task0403; import java.util.Scanner; /* Summation */ public class Solution { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); int temp = 0; while (scanner.hasNextBigInteger()){ if (scanner.hasNext("enter")){ break; } else { int input = scanner.nextInt(); temp+=input; } } System.out.println(temp); System.out.println("ENTER"); } }

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Thomas

Level 31 , Bayreuth, Germany

12 July 2022, 08:35

solution

The problem is the usage of line 13. This one a) checks if the next token inside the stream is a BigInteger. And that BigInteger may be a huuuge number. Far bigger than the int you try to save it in can handle and b) it errors out (without directly printing it) when it does not find a BigInteger as next token. So if you enter "1 2 3 no" then the no would stop the loop. Your check for "enter" never will be reached even if you write "enter". Scanner is a nice class and is very useful when you know its subtleties. Here I suggest to read entire lines from the console (and for that you can use a reader, too) and, if the input does not match "enter" you convert that input into an int and add it to the sum. Oh, and I think you shouldn't output "ENTER" at the end

Alex Tor

Level 22 , Bulgaria

12 July 2022, 09:23

Thank you Thomas, once you clarified there is no need ''ENTER'' to be outputted - I've managed to find out the solution :)

Alex Tor

Level 22 , Bulgaria

12 July 2022, 09:26

changed it to: while (scanner.hasNextInt() && !scanner.hasNext("enter")){

Thomas

Level 31 , Bayreuth, Germany

12 July 2022, 12:19

useful

Ahh, OK, thanks for the feedback. Then validation is very restrained in this task. The condition you additionally added after && never gets evaluated. Same as in your original code. See, if you do not enter an int, then the loop stops. It does not get to the point where it checks if the entered value is "ENTER". Once one part of the condition is false the entire condition is false. For me that would be one way to code it. But it'll throw an exception if you enter anything except ints or ENTER

BufferedReader console = new BufferedReader(new InputStreamReader(System.in));
int sum = 0;
String line;
while (!(line = console.readLine()).equals("ENTER")) {
    sum += Integer.parseInt(line);
}
System.out.println(sum);

You can do that with scanner, too. Just replace readLine() with nextLine(). It does what I tried to describe above. It reads a line and compares it to "ENTER" if doesn't match, then the input gets converted to an int and added to the sum variable. As said anything else than ints and ENTER will throw an exception. That'll need some extra code you learn later.

Alex Tor

Level 22 , Bulgaria

12 July 2022, 15:19

Thank you once again mate, it seems I didn't get your point at first sight, now it's fully clear. Indeed, my code may pass validation and it did but in fact it's half-broken as it can work only in one possible scenario, while others would bring errors. Really appreciate your time and efforts!