Taking User Input in Java

Taking InputTaking Input
JavaJava
Md. Eftakhairul IslamMd. Eftakhairul Islam
eftakhairul@gmail.comeftakhairul@gmail.com
http://eftakhairul.wordpress.comhttp://eftakhairul.wordpress.com

Scanner ClassScanner Class
The Scanner class is a class inThe Scanner class is a class in
java.util, which allows the user tojava.util, which allows the user to
read values of various types by itsread values of various types by its
method.method.
In Java documentationIn Java documentation
Link:Link: http://java.sun.com/j2se/1.5.0/docs/api/java/util/Scanner.htmlhttp://java.sun.com/j2se/1.5.0/docs/api/java/util/Scanner.html
22http://eftakhairul.worldpress.comhttp://eftakhairul.worldpress.com

Scanner Class MethodsScanner Class Methods
BRAC University Computer ClubBRAC University Computer Club 33
Method Returns
int nextInt() Returns the next token as an int.
long nextLong() Returns the next token as a long
float nextFloat() Returns the next token as a float.
double nextDouble() Returns the next token as a long
String next() Finds and returns the next
complete token from this scanner
and returns it as a string; a token
is usually ended by whitespace
such as a blank or line break
String nextLine() Returns the rest of the current line,
excluding any line separator at the
end.

//Import the class//Import the class
import java.util.Scanner;import java.util.Scanner;
public class NumericInput{public class NumericInput{
public static void main(String[] args){public static void main(String[] args){
// Declarations// Declarations
Scanner in = new Scanner(System.in);Scanner in = new Scanner(System.in);
int integer = in.nextInt();int integer = in.nextInt();
long longInteger = in.nextLong();long longInteger = in.nextLong();
float realNumber = in.nextFloat();float realNumber = in.nextFloat();
double doubleReal = in.nextDouble();double doubleReal = in.nextDouble();
String stringLine = in.nextLine();String stringLine = in.nextLine();
String stringStoken= in.next();String stringStoken= in.next();
System.out.println("Enter an integer = “+ integer+”, a longSystem.out.println("Enter an integer = “+ integer+”, a long
integer =“+ longInteger +“,a floating-point = “+ doubleReal+”integer =“+ longInteger +“,a floating-point = “+ doubleReal+”
,and a string = “+ stringStoken+”, It will print whole line = “+,and a string = “+ stringStoken+”, It will print whole line = “+
stringLine);stringLine);
} }} }
Scanner Class ExampleScanner Class Example

55
BufferedReaderBufferedReader
import java.io.*;import java.io.*;
Public class Taking inputPublic class Taking input
{{
Public static void main(String [] args)Public static void main(String [] args) throws IOExceptionthrows IOException
{{
BufferedReader x = new BufferedReader(newBufferedReader x = new BufferedReader(new
InputStreamReader(System.in));InputStreamReader(System.in));
//// String box;String box;
//String box=x.readLine();//String box=x.readLine();
Converting x in IntegerConverting x in Integer
int n=Integer.parseInt(int n=Integer.parseInt(xx.readLine());.readLine());
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66
//Converting x in Float//Converting x in Float
float f=Float.parseFloat(x.readLine());float f=Float.parseFloat(x.readLine());
//Converting x in Double//Converting x in Double
double d=Double.parseDouble(x.readLine());double d=Double.parseDouble(x.readLine());
//Converting x in Long//Converting x in Long
long l=Long.parseLong(x.readLine());long l=Long.parseLong(x.readLine());
//Converting x in Byte//Converting x in Byte
byte b=Byte.parseByte(x.readLine());byte b=Byte.parseByte(x.readLine());
}}
}}

77
JOptionPaneJOptionPane
//importing class from java//importing class from java
Import javax.swing.JOptionPane.*;Import javax.swing.JOptionPane.*;
Main()………Main()………
String s = JOptionPane.showInputDialog ("String s = JOptionPane.showInputDialog ("Enter anyEnter any
numbernumber");");
//Converting x in integer//Converting x in integer
int p = Integer.parseInt(x);int p = Integer.parseInt(x);
//Converting x in Double//Converting x in Double
double d = Double.parseDouble(x.readLine());double d = Double.parseDouble(x.readLine());

Take input from fileTake input from file
// Declarations// Declarations
Scanner inFile = new Scanner(newScanner inFile = new Scanner(new
FileReader("File name with directories"));FileReader("File name with directories"));
//Read token by token from file//Read token by token from file
String stringStoken= inFile.next();String stringStoken= inFile.next();
//Read Line by Line from file//Read Line by Line from file
String stringLine = inFile.nextLine();String stringLine = inFile.nextLine();

Reading data from InternetReading data from Internet
 import java.net.*;import java.net.*;
 import java.io.*;import java.io.*;
 public class WebSiteReader {public class WebSiteReader {
 public static void main(String args[]){public static void main(String args[]){
 String nextLine;String nextLine;
 try{try{
 // Create the URL obect that points & at the default file index.html// Create the URL obect that points & at the default file index.html
 URL url = new URL("http://rainbd.freelance.com.bd/index.html" );URL url = new URL("http://rainbd.freelance.com.bd/index.html" );
 URLConnection urlConn = url.openConnection();URLConnection urlConn = url.openConnection();
 BufferedReader buff= new BufferedReader(newBufferedReader buff= new BufferedReader(new
InputStreamReader(urlConn.getInputStream()));InputStreamReader(urlConn.getInputStream()));
 // Read and print the lines from index.html// Read and print the lines from index.html
 while (true){while (true){
 nextLine =buff.readLine();nextLine =buff.readLine();
 if (nextLine !=null){if (nextLine !=null){
 System.out.println(nextLine);System.out.println(nextLine);
 }else{}else{
 break;break;
 }}
 }}
 } catch(Exception e){} catch(Exception e){
 System.out.println("Please read the exception carefully:" + e.toString());System.out.println("Please read the exception carefully:" + e.toString());
 } } }} } }
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1010
Difference between println & printDifference between println & print
System.out.println(“java”);System.out.println(“java”);
System.out.println(“world”);System.out.println(“world”);
>>
JavaJava
worldworld
>>
(Different line )(Different line )

1111
System.out.print()System.out.print()
System.out.print(“java”);System.out.print(“java”);
System.out.print(“world”);System.out.print(“world”);
>>
javaworld>javaworld>
(Same line)(Same line)

1212
out.println( );out.println( );
import static java.lang.System.out;import static java.lang.System.out;
main()…….main()…….
out.println(“shortcut of println”);out.println(“shortcut of println”);
out.print(“shortcut of print”);out.print(“shortcut of print”);

1313
…….Thank You…..Thank You….

Taking User Input in Java

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