Upper and Lower Case

The program has also been improved by accepting input from the user. The program uses the charAt( int index ) method of the String class. This method returns a single character from a string. The first character in a string is at index 0, the next is at index 1, and so on. (Remember: a String is an object, even if it contains only one character. The charAt() method must be used here to get a char that can be used in the switch.)

import java.io.*;
class Switcher
{
  public static void main ( String[] args ) throws IOException
  {
    String lineIn;
    char   color  ;    
    String message = "Color is";
    
    BufferedReader stdin = new BufferedReader
      ( new InputStreamReader(System.in) );

    System.out.println("Enter a color letter:");
    lineIn = stdin.readLine();
    color = lineIn.charAt( 0 );  // get the first character

    switch ( color )
    {
    
      case 'r':
      case 'R':
        message = message + " red" ;
        break;
               
      case 'o':                  
      case 'O':
        message = message + " orange" ;
        break;
               
      case 'y':                  
      case 'Y':
        message = message + " yellow" ;
        break;
               
      case 'g':                  
      case 'G':
        message = message + " green" ;
        break;
               
      case 'b':  
      case 'B':
        message = message + " blue" ;
        break;
               
      case 'v':  
      case 'V':
        message = message + " violet" ;
        break;
                        
      default:
        message = message + " unknown" ;
            
    }

  System.out.println ( message ) ;
  }
}

    switch ( lineIn )
    {
    
      case "red":
      case "Red":
        message = message + " red" ;
        break;

    . . . and so on