2.0 FUNDAMENTALS OF JAVA PROGRAMMING LANGUAGE

1. 2.0 FUNDAMENTALS OF JAVA PROGRAMMING LANGUAGE 2.4 Apply Input and Output Streams

2. FP301 OBJECT ORIENTED PROGRAMMING Learning Outcome Subtopic 2.4

3. FP301 OBJECT ORIENTED PROGRAMMING INPUT & OUTPUT STREAM • Input stream refers to the flow of data to a program from an input device (System.in). • Output stream refers to the flow of data from a program to an output device (System.out).

4. FP301 OBJECT ORIENTED PROGRAMMING INPUT & OUTPUT STREAM • 1. To display output used : • System.out.print • or • System.out.println • 2. To read input data from user used : • System.in

5. FP301 OBJECT ORIENTED PROGRAMMING InputStreamReader & OutputStreamReader • An InputStreamReader is a bridge from byte streams to character streams • It reads bytes and decodes them into characters using a specified charset. • The charset that it uses may be specified by name or may be given explicitly, or the platform's default charset may be accepted.

6. InputStreamReader Class • Offers backward compatibility with older input streams Example: System.in • Constructors InputStreamReader(InputStream input) – connects an input stream to the reader InputStreamReader(InputStream input, String encoding) – connects an input stream to the reader using the specified encoding form • Methods String getEncoding( ) – returns the name of the character encoding used by the

7. The Use of InputStreamReader & BufferedReader Example 1 import java.io.*; //This is a package to be used while using input and output statements in a program class Act2G { public static void main (String args[]) throws IOException { BufferedReaderstdin = new BufferedReader (new InputStreamReader(System.in)); //This is to enable input from keyboard String str; System.out.println("Enter the data : "); str = stdin.readLine(); //Text data is received from the standard input device, keyboard System.out.println("You have entered: " + str); } }

8. Cont.. Example 2 import java.io.*; public class InputStreamToReaderDemo { public static void main(String args[]) { try { System.out.print ("Please enter your name : "); // Get the input stream representing standard input InputStream input = System.in; // Create an InputStreamReader InputStreamReader reader = new InputStreamReader ( input ); // Connect to a buffered reader, to use the readLine() method BufferedReaderbufReader = new BufferedReader ( reader ); String name = bufReader.readLine(); System.out.println ("Pleased to meet you, " + name); } catch (IOExceptionioe) { System.err.println ("I/O error : " + ioe); } } }