How to properly scan for user input using java.util.Scanner?

Question

I've implemented the following code to print a phrase in lower case characters:

import java.util.Scanner;

public class LowerCase{ 
    public static void main (String[] args) {
        String input, output = "", inter;
        Scanner scan, lineScan;
        scan = new Scanner(System.in); // Scan from the keyboard
        System.out.println("Enter a line of text: ");
        input = scan.nextLine(); // Scan the line of text

        lineScan = new Scanner(input);
        while (lineScan.hasNext()) {
            inter = scan.next();
            output += inter.toLowerCase() + " ";
        }
        System.out.println(output);
    }
}

I don't know what is wrong with my implementation! It compiles normally but when I run the code and type the input phrase, it freezes.

Answer 1

Your loop is waiting for lines with one scanner, but reading lines from another Scanner (thus an infinite loop). This

while (lineScan.hasNext()) {
    inter= scan.next();

should be something like

while (lineScan.hasNext()) {
    inter= lineScan.next();

Answer 2

You do not need two Scanner Objects to achieve the output this shall work for you

scan= new Scanner(System.in); //scan from the keyboard
System.out.println("Enter a line of text: ");
input=scan.nextLine(); //scan the line of text


System.out.println(input.toLowerCase());
scan.close();

Answer 3

I recommend a different method:

import java.util.*;
public class something
  {
      static Scanner reader=new Scanner(System.in);
      public static void main(String[] args)
      {
          System.out.println("type something (string)");
          String text = reader.next();  // whatever the user typed is stored as a string here
          System.out.println(text);

          System.out.println("type something (int)");
          int num = reader.nextInt();  // whatever the user typed is stored as an int here
          System.out.println(num);

          System.out.println("type something (double)");
          double doub = reader.nextDouble(); // whatever the user typed is stored as double here
          System.out.println(doub);
        }
    }

this is some example code for how I get user input.