import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.IOException;

/** 
   A class to read strings and numbers from an input stream.
   This class is suitable for beginning Java programmers.
   It constructs the necessary buffered reader, 
   handles I/O exceptions, and converts strings to numbers.
*/

public class ConsoleReader
{  /**
      Constructs a console reader from an input stream
      such as System.in
      @param inStream an input stream 
   */
   public ConsoleReader(InputStream inStream)
   {  reader = new BufferedReader
         (new InputStreamReader(inStream)); 
   }
   
   /**
      Reads a line of input and converts it into an integer.
      The input line must contain nothing but an integer.
      Not even added white space is allowed.
      @return the integer that the user typed
   */
   public int readInt() 
   {  String inputString = readLine();
      int n = Integer.parseInt(inputString);
      return n;
   }
   
   /**
      Reads a line of input and converts it into a floating-
      point number. The input line must contain nothing but 
      a nunber. Not even added white space is allowed.
      @return the number that the user typed
   */
   public double readDouble() 
   {  String inputString = readLine();
      double x = Double.parseDouble(inputString);
      return x;
   }
   
   /**
      Reads a line of input. In the (unlikely) event
      of an IOException, the program terminates. 
      @return the line of input that the user typed, null
      at the end of input
   */
   public String readLine() 
   {  String inputLine = "";

      try
      {  inputLine = reader.readLine();
      }
      catch(IOException e)
      {  System.out.println(e);
         System.exit(1);
      }

      return inputLine;
   }

   private BufferedReader reader; 
}