Adding multiple numbers using java

Question

I am trying to add numbers by scanning a line. I wanted the answer to be computed soon after i press "ENTER". What is the argument i should pass for the delimiter.

import java.io.*;
import java.util.*;
class add {
   public static void main(String[] args) throws IOException {
      int b=0;
      List<Integer> list  =  new ArrayList<Integer>();
      System.out.println("Enter the numbers");
      Scanner sc = new Scanner(System.in).useDelimiter(" ");
      while(sc.hasNextInt())
      {  
      list.add(sc.nextInt());
       }
      for(int i=0;i<list.size();i++) {
         b += list.get(i);
      }
      System.out.println("The answer is" + b);
   }
}

jlordo · Accepted Answer · 2013-05-18 11:30:42Z

5

Simply write

Scanner sc = new Scanner(System.in);
while (sc.hasNextInt()) {
    list.add(sc.nextInt());
}

This will compute the result as soon as the first non integer is entered...

If you really only want to read one line of input, you need to do this:

Scanner sc = new Scanner(System.in);
String line = sc.nextLine();
for (String token : line.split("\\s+")) {
    list.add(Integer.parseInt(token));
}
// your for loop here...

edited May 18, 2013 at 11:30

answered May 18, 2013 at 11:22

jlordo

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9 Comments

johnchen902 Over a year ago

Koneri said: I wanted the answer to be computed soon after i press enter. Your Scanner won't stop when user press enter.

Konstantin Yovkov Over a year ago

What do you mean by soon ?

johnchen902 Over a year ago

@kocko I think Koneri means as soon as.

Maroun Over a year ago

I think he means "when", so this is a valid answer :)

Koneri Over a year ago

@kocko i tried that already. it still waits for '/'(basically any character apart from integer to mark as end of inputs) to compute the result

|

Mateusz · Accepted Answer · 2013-05-18 11:25:31Z

0

You're adding one item to the list and then your condition for loop stop is i >= list.size(); and list.size() is 0. That's not what you want, you'd like to try

int amount = in.nextInt();
for (int i = 0; i < amount; i++)

Then you probably want to add items to list using list.add(in.nextInt());

answered May 18, 2013 at 11:25

Mateusz

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Comments

StreamingBits · Accepted Answer · 2014-03-12 16:21:44Z

0

import java.io.*;
import java.util.*;
class add {
   public static void main(String[] args) throws IOException {
      int b=0;
      List<Integer> list  =  new ArrayList<Integer>();
      System.out.println("Enter the numbers");
      Scanner sc = new Scanner(System.in).useDelimiter("[\r\n/]");
      while(sc.hasNextInt())
      {  
      list.add(sc.nextInt());

      }
      for(int i=0;i<list.size();i++) {
         b += list.get(i);
      }
      System.out.println("The answer is" + b);
   }
}

answered Mar 12, 2014 at 16:21

StreamingBits

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1 Comment

StreamingBits Over a year ago

use the argument "[\r\n/]" as it is the carriage return character

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