Reading Input -- the Keyboard Class

Reading Input --the Keyboard Class

The Keyboard class is NOT part of the Java standard class libraryThe Keyboard class is in package cs1.It provides several static methods for reading particular types of data from standard input.

public static String readString() public static String readWord() public static boolean readBoolean() public static char readChar() public static int readInt() public static long readLong() public static float readFloat() public static double readDouble()

import cs1.Keyboard;public class ReadKeyboardUsingKeyboardClass{ public static void main(String[] args) { int qty; double price, amountDue; System.out.print("Enter quantity purchased: "); qty = Keyboard.readInt(); System.out.print("Enter the unit price: "); price = Keyboard.readDouble(); amountDue = price * qty; System.out.println("Amount due: " + amountDue); }}

Keyboard Code Example

Install Keyboard – Method 1

Copy the cs1.jar file Paste it in the C:\jdk1.3\jre\lib\ext

directory If the above doesn’t work by itself,

then also paste it in C:\Program Files\JavaSoft\JRE\1.3\lib\ext

Install Keyboard – Method 2

Create a cs1 subdirectory to the directory containing your java programsCopy and compile Keyboard.java into the cs1 subdirectory

Homework directory      |      +-Java source files      |      +- cs1 subdirectory          |          +- Keyboard.java

+- Keyboard.class

Install Keyboard – Method 3

Copy Keyboard.java into the same directory as your programs. Remove the import statement from the code that calls Keyboard

Reading Input –JOptionPaneimport javax.swing.JOptionPane;public class ReadKeyboardViaJOptionPane{ public static void main(String[] args) { int qty; double price, amountDue; String temp; temp = JOptionPane.showInputDialog ("Please enter the quantity purchased: "); qty = Integer.parseInt(temp); temp = JOptionPane.showInputDialog

("Please enter the unit price: "); price = Double.parseDouble(temp); amountDue = price * qty; JOptionPane.showMessageDialog

(null,"Amount due: " + amountDue); }}

Reading Input – java.ioimport java.io.*;public class ReadKeyboardViaSystemIn{ public static void main(String[] args) throws IOException { int qty; double price, amountDue; BufferedReader br = new BufferedReader

(new InputStreamReader (System.in)); System.out.print("Please enter the quantity purchased: "); qty = Integer.parseInt(br.readLine()); System.out.print("Please enter the unit price: "); price = Double.parseDouble(br.readLine()); amountDue = price * qty; System.out.println("Amount due: " + amountDue); }}