.nextLine() method does not take subsequent String inputs

Question

I have a program that asks the user for an input of numbers and characters. For this I am using a Scanner class. But when I take two subsequent string inputs, the console just moves and asks the user to input the second string. The user is unable to input the first string. I have attached my code below to be more specific.

import java.util.Scanner;

class XYZ {

    public static void main(String args[]) {
        int x, y, z, b, c;
        String p, q;
        Scanner sc = new Scanner(System.in);

        System.out.println("Enter a number");
        b = sc.nextInt();

        System.out.println("Enter a new number");
        c = sc.nextInt();

        System.out.println("Enter a String");
        p = sc.nextLine();

        System.out.println("Enter a new String");
        q = sc.nextLine();

        System.out.println("Enter a number");
        x = sc.nextInt();

        System.out.println("Enter 2nd number");
        y = sc.nextInt();

        System.out.println("Enter 3rd number");
        z = sc.nextInt();

        ABC a = new ABC();

        a.PQR(b, c);
        a.PQR(p, q);
        a.PQR(x, y, z);
    }
}

class ABC {

    void PQR(int a, int b) {
        int res = a + b;
        System.out.println("The sum is" + " " + res);
    }

    void PQR(String a, String b) {
        System.out.println("Thye concataneted string is" + a + " " + b);
    }

    void PQR(int a, int b, int c) {
        int res = a * b * c;
        System.out.println("The product is" + " " + res);
    }
}

Debosmit Ray · Accepted Answer · 2016-03-03T10:41:23.387

4

You need to make a dummy call to nextLine() after your call to nextInt(). The nextInt() isn't taking the "\n" into account.

Alternatively, and preferably, just use nextLine() to accept all input and whichever ones need to be ints, just use:

int i = Integer.parseInt(**string**);

Does this help?

edited Mar 03 '16 at 10:41

answered Mar 03 '16 at 10:28

Debosmit Ray

4,731
2
21
41

I have made a dummy call to next(), but still I am unable to input the first String. Also I want to use the same scanner class object for both integer and String inputs. – Pratik Paul Mar 03 '16 at 10:38
@PratikPaul I mistakenly wrote `next()` instead of `nextLine()`. Sorry about that! – Debosmit Ray Mar 03 '16 at 10:42
I use the listed alternative method extensively in receiving Integer inputs from the console. – shrmn Mar 03 '16 at 10:47
@PratikPaul Yep. That would indeed be the better way for your purposes. – Debosmit Ray Mar 03 '16 at 10:48

score 2 · Answer 2 · edited May 23 '17 at 12:02

2

Thats because the Scanner#nextInt method does not consume the last newline character of your input, and thus that newline is consumed in the next call to Scanner#nextLine.

ref

OR

If you use the nextLine() method immediately following the nextInt() method, recall that nextInt() reads integer tokens, because of this, the last newline character for that line of integer input is still queued in the input buffer and the next nextLine() will be reading the remainder of the integer line (which is empty). - hackerrank.com

Update : After c = sc.nextInt(); you need to put one more statement i.e.

sc.nextLine();

HTH!

edited May 23 '17 at 12:02

Community

1
1

answered Mar 03 '16 at 10:27

Himanshu Bhandari

1,379
1
20
32

So what would be your suggestion to input the first String – Pratik Paul Mar 03 '16 at 10:28
Please find updated answer. – Himanshu Bhandari Mar 03 '16 at 10:40

score 2 · Answer 3 · edited Aug 23 '18 at 22:54

import java.util.Scanner;

public class Solution {
  public static void main(String[] args) {
    Scanner scan = new Scanner(System.in);
    int i = scan.nextInt();
    double d = scan.nextDouble();
    scan.nextLine();
    String s = scan.nextLine();

    // Write your code here.

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

score 1 · Answer 4 · edited Oct 13 '16 at 16:40

import java.util.Scanner;

public class Solution {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int i = sc.nextInt();
        sc.nextLine();
        double d = sc.nextDouble();
        sc.nextLine();
        String s = sc.nextLine();

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

To take three lines of input: int,double and String

score 1 · Answer 5 · edited Aug 23 '18 at 22:17

1

If you use the nextLine() method immediately following the nextInt() method, recall that the nextInt() reads integer tokens; because of this, the last newline character for that line of integer input is still queued in the input buffer and the next nextLine() will be reading the remainder of the integer line (which is empty).

That's why the console asks the user to input the second string, so you can use

Scanner md = new Scanner(System.in);
int n      = md.nextInt();  //before using the input stream for string
String st  = md.nextLine();

edited Aug 23 '18 at 22:17

zx485

24,099
26
45
52

answered Aug 23 '18 at 21:54

mayankD

36
3

@zx485 i will do it from the next time thanks – mayankD Aug 23 '18 at 22:27

.nextLine() method does not take subsequent String inputs

5 Answers5