Scanner in for loop, loops once before getting any input

Question

    Scanner scan = new Scanner(System.in);
    String in;
    int count = scan.nextInt();
    for (int i = 0; i < count; i++){
        System.out.print("Input "+i+" of "+count+": ");
        in = scan.nextLine();
    }

As the title says, this for loop prints the line twice (with the "i" variable incremented once) before it stops to wait for user input. I don't understand why it does that. I tried to use while loop, with similar results. Help?

add a simple scan.next(); or scan.nextLine(); after your scan.nextInt(); and before your loop. or read a String in the first statement, and parse it to an int. — Stultuske, Sep 02 '19 at 12:53

score 1 · Answer 1 · edited Sep 02 '19 at 12:58

1

You should add scan.nextLine(); after scan.Int();.

Scanner scan = new Scanner(System.in);
String in;
int count = scan.nextInt();
scan.nextLine();

edited Sep 02 '19 at 12:58

answered Sep 02 '19 at 12:57

Abnaby

45
8

score 0 · Answer 2 · answered Sep 02 '19 at 12:56

Try this :

Scanner scan = new Scanner(System.in);
String in;
int count = Integer.parseInt(scan.next());
for (int i = 0; i < count; i++){
    System.out.print("Input "+i+" of "+count+": ");
    in = scan.nextLine();
}

Keep in mind, you need to handle NaN exception

Alternative, as suggested by @Stultuske in a comment, add scan.nextLine(); or scan.next(); after scan.nextInt();

Scanner in for loop, loops once before getting any input

2 Answers2