如何通过键盘在Java中引入数字

Question

What do I have to do in order to introduce numbers by keyboard in Java on eclipse which are the libraries? What is the command to read that? Do I have to write libraries or eclipse do it automatically?

Answer 1

This is simple program to get user input import java.util.Scanner;

class GetInputFromUser
{
   public static void main(String args[])
   {
      int a;
      float b;
      String s;

      Scanner in = new Scanner(System.in);

      System.out.println("Enter a string");
      s = in.nextLine();
      System.out.println("You entered string "+s);

      System.out.println("Enter an integer");
      a = in.nextInt();
      System.out.println("You entered integer "+a);

      System.out.println("Enter a float");
      b = in.nextFloat();
      System.out.println("You entered float "+b);   
   }
}

Answer 2

Sounds like you're asking how to get a number input from the keyboard in Java...I think...It's hard to understand what you're asking. If that's what you're asking, well, try this:

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

class InputNumber
{
    public static void main (String[] args) throws java.lang.Exception
    {
        Scanner in = new Scanner (System.in); 
        int number; 
        System.out.println ("enter a number"); 
        number=in.nextInt(); 
        System.out.println("You entered: " + number);
    }
}

Answer 3

You can use the IO library provided by Java. You need to import java.io.* for this.

Create a BufferedReader which can take String as input. Once a String is input, you can parse it to whatever suits you, with a corresponding parser from the wrapper class.

eg

BufferedReader in = new BufferedReader (new InputStreamReader (System.in));
String input = in.readLine();
int num = Integer.parseInt(input);