CODEWITHSUNDEEP
javajava.util.scanneruser-input
Naman Sharma
Naman Sharma

Reputation: 53

Call to nextLine() needed thrice for reading a string after it has read int and double in java

import java.util.Scanner;

public class Solution {
    public static void main(String[] args) {
        /* Read input */
        Scanner scan = new Scanner(System.in);
        int i    = scan.nextInt();
        double d = scan.nextDouble();
        scan.nextLine();              // gets rid of the pesky newline
        String s = scan.nextLine();
        scan.close();
        
        /* Print output */
        System.out.println("String: " + s);
        System.out.println("Double: " + d);
        System.out.println("Int: " + i);
    }
}

The above code works perfectly fine in hackerrank compiler. While if i run it on IntelliJ, one extra call to scan.nextLine() is required in order to read the actual string.

import java.util.Scanner;

public class Solution {
    public static void main(String[] args) {
        /* Read input */
        Scanner scan = new Scanner(System.in);
        int i    = scan.nextInt();
        double d = scan.nextDouble();
        scan.nextLine();              // gets rid of the pesky newline
        scan.nextLine();              // gets rid of the pesky newline
        String s = scan.nextLine();
        scan.close();

        /* Print output */
        System.out.println("String: " + s);
        System.out.println("Double: " + d);
        System.out.println("Int: " + i);
    }
}

Can someone help me with why this could happen? I am assuming the call to nextDouble() would ignore the \n left in the buffer by nextInt() and pickup the next double token and leave a new \n in the buffer. So a single call to nextLine() should be enough to clear that \n from buffer, but why 2 calls are needed when I run this on IntelliJ.

Is this a JAVA version issue or is there something really basic which I am missing?

Upvotes: 0

Views: 68

Answers (1)

cyberbrain
cyberbrain

Reputation: 5075

You probably see the effect of this official IDEA issue: Console readLine skips input in 2022.1.1

You could update to 2022.1.2 where this is fixed.

Upvotes: 1

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