The document discusses different ways to read input in Java programs, including using System.in.read() to read a single character, stream classes which are flexible but complex, and the Scanner class which was added in JDK 1.5 and is easy to use. It provides details on using the Scanner class, noting that an object is created from a source such as the keyboard, file, or network, and methods are used to read the appropriate data type from the source. Common Scanner methods are listed that can read primitive types and strings.

1. Reading Input
In JAVA
-M Vishnuvardhan,
Dept. of Computer Science,
SSBN Degree College, ATP

2. SSBN Degree College, ATP M Vishnuvardhan
Introduction
Java primarily developed for Graphical User Interface, for this
reason Java doesn’t have explicit statement like scanf(). But however
we can read input into java program using the following ways.
1.Using System.in.read(): reads only one char in form of unicode
2.Using Stream classes (defined in java.io): very flexible and lot of
features provided. But they are bit complex and needs experience in
writing the programs
3.Using Scanner class (defined in java.util): very easy to use. Added
after jdk 1.5.0 only.

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How to read data using Scanner
The following steps are to be taken in order to read data
from Scanner class
1.Import util package (import java.util.*;)
2.Create an object to Scanner class
Scanner objName=new Scanner (Source);
1.Use appropriate method to read required data

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What is a source
Means from where the data is read in to the program. The source can
be keyboard, File on HDD, network computer, internet …
E.g: Scanner s=new Scanner (System.in);
Scanner s= new Scanner (new File(“D:Sample.txt”));
Source ProgramReading
Keyboard – System.in
File - FileReader or FileInputStream or File
Network – Socket

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Scanner methods
Scanner defines a rich set of methods
General Syntax
byte nextByte():
short nextShort():
int nextInt():
long nextLong():
Note: no explicit method to read single char in java
(i.e., there is no nextChar() )
 float nextFloat():
 double nextDouble():
 boolean nextBoolean():
 String next():
 String nextLine():
xxx nextXxx():

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Questions

7. SSBN Degree College, ATP M Vishnuvardhan
Questions