/**
   An easy interface to read numbers and strings from 
   standard input
 
   @version 1.10 10 Mar 1997
   @author Cay Horstmann

*/
 
public class Console
{  /**
      print a prompt on the console but don't print a newline
      @param prompt the prompt string to display
    */

   public static void printPrompt(String prompt)
   {
     System.out.print(prompt);
     System.out.flush();
   }
   
   /**
      read a string from the console. The string is 
      terminated by a newline
 
      @return the input string (without the newline)
    */
    
   public static String readLine()
   {  
   
   int ch;
   
   String r = "";
   
   boolean done = false;
   
   while (!done)
   {  
      try
      {  
         ch = System.in.read();
         if (ch < 0 || (char)ch == '\n')
            done = true;
         else if ((char)ch != '\r') // weird--it used to do \r\n translation
            r = r + (char) ch;
         }
         catch(java.io.IOException e)
         {
            done = true;
         }
      }
      return r;
   }
 
   /**
      read a string from the console. The string is 
      terminated by a newline
 
      @param prompt the prompt string to display
      @return the input string (without the newline)
    */
    
   public static String readLine(String prompt)
   {
      printPrompt(prompt);
      return readLine();
   }
 
   /**
      read an integer from the console. The input is 
      terminated by a newline
 
      @param prompt the prompt string to display
      @return the input value as an int
      @exception NumberFormatException if bad input
    */
    
   public static int readInt(String prompt)
   {  
      while(true)
      {  
         printPrompt(prompt);
         try
         {  
            return Integer.valueOf(readLine().trim()).intValue();
         }
         catch(NumberFormatException e)
         {
            System.out.println("Not an integer. Please try again!");
         }
      }
   }
 
   /**
      read a floating point number from the console. 
      The input is terminated by a newline
 
      @param prompt the prompt string to display
      @return the input value as a double
      @exception NumberFormatException if bad input
    */
    
   public static double readDouble(String prompt)
   {
      while(true)
      {
         printPrompt(prompt);
         try
         {
            return Double.parseDouble(readLine().trim());
         }
         catch(NumberFormatException e)
         {
            System.out.println("Not a floating point number. Please try again!");
         }
      }
   }
}