title: detect space in string
body: <p>How do I determine if a space is in the input entered by the user? The user's input is stored in a string. The part I'm referring to is in between the asterisks. I read that regex could be used but I do not know how to use it to detect if there is a space in the string s.   </p>
  
  <pre><code>import java.util.Scanner;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  
  public class LAnalyze{
  
  public static void main(String[] args) {
  
      int j = 0;
      String s = null;
      Scanner scan = new Scanner(System.in);
  
  
      System.out.println("Enter an input:  ");
      s = scan.nextLine();
  
      ****************************************************
                Pattern pattern = Pattern.compile("\\s");
      Matcher matcher = pattern.matcher(s);
      boolean found = matcher.find(); 
  
      if(spaceIsFound)
               *******************************************************
      {
          System.out.println("Invalid character(s) entered.. Program terminated!\n");
          System.exit(0);
      }
      else if( s.charAt(0)=='a'||s.charAt(0)=='b'||s.charAt(0)=='c'||s.charAt(0)=='d'||s.charAt(0)=='e'||s.charAt(0)=='f'||
              s.charAt(0)=='g'||s.charAt(0)=='h'||s.charAt(0)=='i'||s.charAt(0)=='j'||s.charAt(0)=='k'||s.charAt(0)=='l'||
              s.charAt(0)=='m'||s.charAt(0)=='n'||s.charAt(0)=='o'||s.charAt(0)=='p'||s.charAt(0)=='q'||s.charAt(0)=='r'||
              s.charAt(0)=='s'||s.charAt(0)=='t'||s.charAt(0)=='u'||s.charAt(0)=='v'||s.charAt(0)=='w'||s.charAt(0)=='x'||
              s.charAt(0)=='y'||s.charAt(0)=='z'||s.charAt(0)=='A'||s.charAt(0)=='B'||s.charAt(0)=='C'||s.charAt(0)=='D'||
              s.charAt(0)=='E'||s.charAt(0)=='F'||s.charAt(0)=='G'||s.charAt(0)=='H'||s.charAt(0)=='I'||s.charAt(0)=='J'||
              s.charAt(0)=='K'||s.charAt(0)=='L'||s.charAt(0)=='M'||s.charAt(0)=='N'||s.charAt(0)=='O'||s.charAt(0)=='P'||
              s.charAt(0)=='Q'||s.charAt(0)=='R'||s.charAt(0)=='S'||s.charAt(0)=='T'||s.charAt(0)=='U'||s.charAt(0)=='V'||
              s.charAt(0)=='W'||s.charAt(0)=='X'||s.charAt(0)=='Y'||s.charAt(0)=='Z') {
  
          System.out.print( (s) + ": Identifier\n");
          for (int k = 0; k &lt; s.length(); k++) {  
              j++;
              System.out.println("Token " + (j) + " = " + (s.charAt(k)));
  
          }
      }
      else if(s.charAt(0)=='0'||s.charAt(0)=='1'||s.charAt(0)=='2'||s.charAt(0)=='3'||s.charAt(0)=='4'||s.charAt(0)=='5'||
              s.charAt(0)=='6'||s.charAt(0)=='7'||s.charAt(0)=='8'||s.charAt(0)=='9') {
  
          System.out.print( (s) + ": Unsigned Integer\n");
          for (int m = 0; m &lt; s.length(); m++) {  
              j++;
              System.out.println("Token " + (j) + " = " + (s.charAt(m)));
          }
      }   
      else {
          System.out.println("Invalid character(s) entered.. Program terminated!\n");
          System.exit(0);
      }
  
  }
  </code></pre>
  
  <p>}</p>