Read double from keyboard in Java

Question

How can I read a double variable from keyboard in Java? I\'m trying to solve this, but it didn\'t works. It said:

Exception in thread \"main\" java.util.I

Answer 1

the code you have written is totally correct ,you should check your input order string double int

Answer 2

try this:

import java.io.*;
import java.util.Scanner;

class DoubleDouble
{
   public static void main (String[] args)
   {
      double value;
      Scanner scan = new Scanner( System.in );

      System.out.print("Enter a double:");
      value = scan.nextDouble();

      System.out.println("value: " + value +" twice value: " + 2.0*value );
    }
}

And be sure, that you type: For example: 3.14 so the dot, should be a point

Answer 3

Tried to reproduce, had no luck. I think that the problem is with your input. here is what I have tried:

input:

s

4.51

2

output:

String: s
Double: 4.51
Int: 2

In your code your first scaner takes string, second: double and third takes int.

Answer 4

You can also use BufferedReader Class to take Double as input. It can be taken as

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

String s=br.readLine();

Double d=Double.parseDouble(br.readLine());

int i=Integer.parseInt(br.readLine());