Question

I have this Java input-related problem.
I’m solving some cases in UVAToolkit, but there are some problems that the line input requires from the System.in. Basing from these codes below, how could I terminate the problem once I’ve pressed key? The sample input/output are displayed below.

Scanner scanner = new Scanner(System.in);
String line;
while((line = scanner.nextLine()) != null) {
    System.out.println(line);
}
System.out.println("done");

Sample Input:

1 10
10 100
100 1000

Sample Output:

1 10
10 100
100 1000
done

Thanks in advance.

Answer 1

Don’t check for null input but for an empty string. This way, you should be able to terminate just by pressing the return key.

while(!(line = scanner.nextLine()).equals(""))