Scanner doesn't read whole sentence - difference between next() and nextLine() of scanner class

Question

I'm writing a program which allows the user to input his data then outputs it. Its 3/4 correct but when it arrives at outputting the address it only prints a word lets say only 'Archbishop' from 'Archbishop Street'. How do I fix this?

import java.util.*;

class MyStudentDetails{
    public static void main (String args[]){
        Scanner s = new Scanner(System.in);
        System.out.println("Enter Your Name: ");
        String name = s.next();
        System.out.println("Enter Your Age: ");
        int age = s.nextInt();
        System.out.println("Enter Your E-mail: ");
        String email = s.next();
        System.out.println("Enter Your Address: ");
        String address = s.next();

        System.out.println("Name: "+name);
        System.out.println("Age: "+age);
        System.out.println("E-mail: "+email);
        System.out.println("Address: "+address);
    }
}

score 41 · Answer 1 · edited Jul 30 '16 at 21:25

41

This approach is working, but I don't how, can anyone explain, how does it works..

String s = sc.next();
s += sc.nextLine();

edited Jul 30 '16 at 21:25

Partha Sarathi Samanta

3
1

answered Feb 26 '16 at 03:08

Arvind Ramachandran

411
4
3

14

Because method `nextLine()` reads next symbols from current current line after cursors current position. For example, if your input contains 2 line `1` and `Hello World`. And source like that: `int x = sc.nextInt(); String s = sc.nextLine()`. In this case, after `nextInt()`, the cursor stays after the symbol "1" and this is the end of this line and `nextLine()` reads nothing. But, when you write code as you wrote top, at first, cursor moves to the next line and reads the word "Hello". Then cursor stays right after the word "Hello". And the command `sc.nextLine()` reads next symbols -" World". – Ulphat Aug 12 '16 at 06:03
4

First time ever seen an answer, which itself a question got many upvotes – Ravi Oct 18 '17 at 14:57
1

The **next()** methods scan for tokens (you can think of this as a word) and the **nextLine()** methods read from the Scanner's current location until the beginning of the next line – Arun Mar 27 '18 at 08:49
Suppose inout is : "Hello World I am Java"; then String s = sc.next(); -> will return "Hello" .... Now, according to doc., nextLine() returns "the line that was skipped..." hence, s += sc.nextLine(); will be like -> Hello + World I am Java i.e. final string: "Hello World I am Java" – Prajwal Waingankar Jun 07 '20 at 14:14

score 16 · Answer 2 · answered Mar 10 '15 at 12:36

16

Initialize the Scanner this way so that it delimits input using a new line character.

Scanner sc = new Scanner(System.in).useDelimiter("\\n");

Refer the JavaDoc for more details

Use sc.next() to get the whole line in a String

answered Mar 10 '15 at 12:36

Nomad

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But still \r is coming in String. – Hammad Hassan Oct 24 '16 at 19:58
Able to read the full line with spaces and special characters. Use sc.next().trim() to trim off the [Enter] from user input. – oraclesoon Mar 16 '17 at 09:21
It should be Scanner sc = new Scanner(System.in).useDelimiter("\n"); – azhar baloch Oct 28 '17 at 16:38

Anthony Forloney · Answer 3 · 2010-10-30T13:52:05.657

12

I would use Scanner#nextLine opposed to next for your address attribute.

This method returns the rest of the current line, excluding any line separator at the end.

Since this returns the entire line, delimited by a line separator, it will allow the user to enter any address without any constraint.

edited Oct 30 '10 at 13:52

answered Oct 30 '10 at 13:46

Anthony Forloney

84,001
14
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112

score 6 · Answer 4 · answered Oct 30 '10 at 13:42

6

Default delimiter of Scanner is whitespace. Check javadoc for how to change this.

answered Oct 30 '10 at 13:42

Raghuram

49,195
9
101
120

score 5 · Answer 5 · edited Sep 16 '16 at 07:18

5

String s="Hi";
String s1="";

//For Reading Line by hasNext() of scanner 
 while(scan.hasNext()){
  s1 = scan.nextLine();
 }
System.out.println(s+s1);

/*This Worked Fine for me for reading Entire Line using Scanner*/

edited Sep 16 '16 at 07:18

Frits

6,116
10
39
50

answered Sep 16 '16 at 06:57

Vinayak

1
1
4

score 5 · Answer 6 · answered Oct 30 '10 at 13:43

5

Instead of using System.in and System.out directly, use the Console class - it allows you to display a prompt and read an entire line (thereby fixing your problem) of input in one call:

String address = System.console().readLine("Enter your Address: ");

answered Oct 30 '10 at 13:43

Michael Borgwardt

327,225
74
458
699

Any other simple way, as I have not yet learned about the Console class? – Bonett09 Oct 30 '10 at 13:49
1

@Bonett09: Well, now you've learned about it. It's actually in some ways simpler than using the input and output streams directly. – Michael Borgwardt Oct 30 '10 at 14:03

score 5 · Answer 7 · edited Jan 16 '19 at 10:25

5

import java.util.Scanner;

public class Solution {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        String s = scan.next();
        s += scan.nextLine();
        System.out.println("String: " + s);

    }
}

edited Jan 16 '19 at 10:25

Manoj kumar

440
4
13

answered Nov 14 '18 at 06:07

ayush sharma

51
1
3

score 4 · Answer 8 · answered Oct 18 '17 at 14:46

We can easily done using scan.nextLine .It will read the rest of the input till the end. Then assign it to your variable. Entire sentence can be printed easily . Here is the example for your better understanding.

    String s = "HackerRank ";

    Scanner scan = new Scanner(System.in);


    String s2;



    scan.nextLine(); // read the rest of the line of input (newline character after the double token).
    s2 = scan.nextLine();



    /* Concatenate and print the String variables on a new line integer variables on a new line; 

    System.out.println(s + s2);

    scan.close();

} }

score 3 · Answer 9 · answered Jul 29 '20 at 19:55

next() will only store the input up to the first token. if there are two words "Hi there" it means there are two tokens separated by space (delimiter). Every time you call the next() method it reads only one token.

if input is "Hi there !"

Scanner scan = new Scanner(System.in);
String str = scan.next()
System.out.println(str);

Output

Hi

So if you both the words you need to call next() again to get the next token which is inefficient for longer string input

nextLine() on the other hand grabs the entire line that the user enters even with spaces

Scanner scan = new Scanner(System.in);
String str = scan.nextLine()
System.out.println(str);

Output

Hi there !

score 2 · Answer 10 · edited Jul 17 '17 at 15:13

2

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();
        String s="";
        while(scan.hasNext())
        {
            s=scan.nextLine();
        }

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

edited Jul 17 '17 at 15:13

ρяσѕρєя K

127,886
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answered Jul 17 '17 at 15:08

kallipudi yeswanth

21
1

2

Add some explanation with answer for how this answer help OP in fixing current issue – ρяσѕρєя K Jul 17 '17 at 15:13

score 2 · Answer 11 · edited Nov 14 '18 at 07:45

2

next() can read the input only till the space. It can't read two words separated by space. Also, next() places the cursor in the same line after reading the input.

nextLine() reads input including space between the words (that is, it reads till the end of line \n). Once the input is read, nextLine() positions the cursor in the next line.

for reading the entire line you can use nextLine()

edited Nov 14 '18 at 07:45

Hulk

5,295
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answered Aug 17 '17 at 06:25

Gourab Konar

150
2
13

score 2 · Answer 12 · edited Aug 26 '17 at 09:12

2

I tried following code but this is not stopping as there is no break condition so it always waiting for input , may be you could add a condition for break

public class Solution {

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

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

edited Aug 26 '17 at 09:12

Luciano van der Veekens

5,586
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answered Aug 26 '17 at 03:17

Asid

31
4

1

This does not answer this question. Post your query as new question. – Ravindra babu Aug 26 '17 at 03:25
" String s=""; while(scan.hasNext()) { s=scan.nextLine(); }" is what i was looking for, which prints the whole line. Thanks. – Barani r Nov 17 '18 at 03:06

score 0 · Answer 13 · answered Aug 19 '16 at 19:20

0

To get the whole adress add

s.nextLine();//read the rest of the line as input

before

System.out.println("Enter Your Address: ");
String address = s.next();

answered Aug 19 '16 at 19:20

Bharathi Mohan

1
1

score 0 · Answer 14 · answered Jan 21 '17 at 13:34

I set the token delimiter to be a newline pattern, read the next token, and then put the delimiter back to whatever it was.

public static String readLine(Scanner scanner) {
        Pattern oldDelimiter = scanner.delimiter();
        scanner.useDelimiter("\\r\\n|[\\n\\x0B\\x0C\\r\\u0085\\u2028\\u2029]");
        String r = scanner.next();
        scanner.useDelimiter(oldDelimiter);
        return r;
}

score 0 · Answer 15 · edited Oct 17 '17 at 03:39

0

Below is the sample code to read a line in Standard input using Java Scanner class.

import java.util.Scanner;

public class Solution {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        String s = scan.nextLine();
        System.out.println(s);
        scan.close();
    }
}

Input:

Hello World

Output:

Hello World

edited Oct 17 '17 at 03:39

Tom

14,120
16
41
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answered Sep 19 '17 at 09:23

Satyajit Mishra

23
5

score 0 · Answer 16 · answered Oct 17 '17 at 03:23

"it only prints a word lets say only 'Archbishop' from 'Archbishop Street"

It is only printing the word because Scanner functions such as next(), nextInt(), etc. read only a token at time. Thus this function reads and returns the next token.

For example if you have: x y z
 s.next() will return x
 s.nextLine() y z

Going back to your code if you want to read the whole line "Archbishop Street"

String address = s.next(); // s = "Archbishop"
Then address += s.nextLine(); // s = s + " Street"

score 0 · Answer 17 · answered Nov 07 '17 at 19:03

0

the below piece of code should do what yoiu are looking for:

public static void main(String[] args) {
    Scanner scan = new Scanner(System.in);
    String s = scan.nextLine();
    System.out.println(s);
    scan.close();
}

answered Nov 07 '17 at 19:03

akshaya pandey

827
6
15

score 0 · Answer 18 · answered May 07 '19 at 10:08

java.util.Scanner; util - package, Scanner - Class

next() reads the string before the space. it cannot read anything after it gets the first space.
nextLine() reads the whole line. Read until the end of the line or "/n". Note: Not The Next line

(Example)

My mission in life is not merely to survive, but to thrive;

and to do so with some passion, some compassion, some humor.

(Output)

My
My mission in life is not merely to survive, but to thrive;

Tricks:

If you want to read the next line Check Java has method.

while (scanner.hasNext()) {
    scan.next();
}

while (scanner.hasNext()) {
    scan.nextLine();
}

Darshana Ekanayake · Answer 19 · 2020-08-03T05:21:06.147

0

next() is read until the space of the encounter, and the nextLine() is read to the end of the line. Scanner scan = new Scanner(System.in);
String address = scan.next();
s += scan.nextLine();

edited Aug 03 '20 at 05:21

answered Aug 03 '20 at 05:14

Darshana Ekanayake

464
6
8

score 0 · Answer 20 · answered Dec 13 '20 at 09:50

Scanner scanner = new Scanner(System.in);
String str = scanner.next();
str += scanner.readLine();

String str = scanner.next(); ===> it fetch the 1st word of the line (hello world!! => "hello") str += scanner.nextLine(); ===> This method returns the rest of the current line, excluding any line separator at the end. (hello world!! => " world!!")

score -1 · Answer 21 · edited Oct 18 '16 at 12:52

-1

I had the same question. This should work for you:

s.nextLine();

edited Oct 18 '16 at 12:52

Prasad Khode

5,897
11
38
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answered Jan 31 '16 at 21:15

Eugene Prokopenko

9
2

score -2 · Answer 22 · edited Jun 19 '18 at 07:54

-2

Use nextLine() instead of next() for taking sentence as string input.

Scanner sc = new Scanner(System.in);
String s = sc.nextLine();

edited Jun 19 '18 at 07:54

Abhijith S

492
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answered Mar 19 '16 at 17:21

Akshay Suresh

353
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9

This is actually working. But why this answer is down voted? – Abhijith S Jun 17 '18 at 12:45

score -4 · Answer 23 · answered Jan 15 '14 at 09:00

-4

You can do this:

class MyStudentDetails{
    public static void main (String args[]){
         Scanner s = new Scanner(System.in);
         System.out.println("Enter Your Name: ");
         String name = s.nextLine();
         System.out.println("Enter Your Age: ");
         String age = s.nextLine();
         System.out.println("Enter Your E-mail: ");
         String email = s.nextLine();
         System.out.println("Enter Your Address: ");
         String address = s.nextLine();


         System.out.println("Name: "+name);
         System.out.println("Age: "+age);
         System.out.println("E-mail: "+email);
         System.out.println("Address: "+address);

    }
}

answered Jan 15 '14 at 09:00

user114573

1

1

this answer is incorrect. If you test this code the lines with "s.nextLine();" will return nothing - an empty string. Dont use this answer! – Rubinum Nov 05 '14 at 08:33
@Rubinum This code here is not wrong (logically wrong, yes, but not technically) and if your code returned an empty String, then you failed to use `s.nextLine()` correctly. That's not user114573s fault. – Tom Oct 17 '17 at 03:32

Scanner doesn't read whole sentence - difference between next() and nextLine() of scanner class

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