Chandrika: Created page with ''''Title of script''': '''Taking user input using BufferedReader''' '''Author: Arya Ratish''' '''Keywords: BufferedReader, InputStreamReader, user input, Video tutorial.''' …'

2012-11-27T10:21:39Z

Created page with ''''Title of script''': '''Taking user input using BufferedReader''' '''Author: Arya Ratish''' '''Keywords: BufferedReader, InputStreamReader, user input, Video tutorial.''' …'

New page

'''Title of script''': '''Taking user input using BufferedReader'''

'''Author: Arya Ratish'''

'''Keywords: BufferedReader, InputStreamReader, user input, Video tutorial.'''

{| style="border-spacing:0;"
! <center>Visual Cue</center>
! <center>Narration</center>

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 1
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Welcome to the spoken-tutorial on '''Taking user input''' '''using BufferedReader''' in '''Java.'''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 2
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| In this tutorial we will learn:

* To take user input in Java
* About InputStreamReader and BufferedReader

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 3
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| To follow this tutorial you must know:

* how to write, compile and run a simple java program in '''Eclipse'''
* About the '''datatypes''' in '''Java'''
* If not, please refer to the '''spoken tutorial''' on these topics available at '''spoken''' ''hyphen'' '''tutorial''' ''dot'' '''org.'''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 4
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Here, I am using,

'''Ubuntu 11.04'''

'''JDK 1.6'''

'''Eclipse 3.7.0'''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 5
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Now, we will learn what a '''BufferedReader '''is.

It is a '''class''' which is used to read text from an input stream.

It provides efficient way to read array of characters and lines.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 6
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| To make use of this, we need to import three '''classes''' from the''' java '''''dot''''' io package.'''

These three '''classes''' are:

* '''BufferedReader'''
* '''InputStreamReader'''
* '''IOException'''

We will learn about''' packages''' and how to import '''classes''' in the coming tutorials.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 6
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| All the input that we take from the user will be in the form of '''String'''.

It has to be then typecasted or converted to the particular datatype.

We will see that while we write our program to take the user input.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 7
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Now, let us see the syntax to implement '''BufferedReader'''.

Once you import the three '''classes,''' you need to create an object of '''BufferedReader'''.

You also need to create an '''object''' of '''InputStreamReader'''.

We will learn about this in detail when we write our program.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Switch to Eclipse

Open the class '''InputBufferedReader'''

Type,

'''import java.io.IOException;'''

'''import java.io.InputStreamReader;'''

'''import java.io.BufferedReader;'''

| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| So, let us switch to '''Eclipse'''.

I have already opened a '''class''' named '''InputBufferedReader'''.

We will begin with importing the '''java.io package'''.

So type, before the class '''import''' ''space'' '''java''' ''dot'' '''io '''''dot'' star semi colon.

This will import the classes '''InputStreamReader, BufferedReader and IOException.'''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''Type'''

'''<nowiki>public static void main(String[] args) </nowiki>throws IOException{'''

'''}'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| We will make use of '''BufferedReader '''inside the main method.

We need to throw an '''IOException''' in whatever method we use the '''BufferedReader'''.

So right after the main method type '''throws IOException.'''

Now, what does this mean?

'''Exceptions '''are errors which occur in Java when some unexpected circumstances occur.

To prevent '''Exception errors '''we make use of '''throws '''keyword.

'''Throws '''is a keyword which is used during '''Exception handling. '''

It is used whenever we know that '''Exception error''' will definitely occur.

When we use '''BufferedReader, exception error''' always take place.

To prevent '''Exception errors''' from taking place we make use of '''throws IOException.'''

We will learn about '''Exception Handling''' in the coming tutorials.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Inside main method,

Type,

'''InputStreamReader isr=new InputStreamReader(System.in);'''

'''BufferedReader br = new BufferedReader(isr);'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Now, we will create an '''object''' of '''InputStreamReader'''.

For that, type '''InputStreamReader''' ''space'' '''isr''' ''equalto'' '''new''' ''space'' '''InputStreamReader''' and parentheses.

Inside the parentheses, type '''System''' ''dot'' '''in '''and then semicolon.

'''InputStreamReader '''is a '''class''' which allows us to take input from the user.

'''System '''''dot''''' in '''tells the''' java compiler''' to take '''input''' from the user using keyboard.

The input that '''System '''''dot '''''in '''takes is stored in the '''object''' of '''InputStreamReader '''for sometime'''.'''

After this we create an '''object''' of '''BufferedReader'''.

So type, '''BufferedReader''' '''br''' ''equal to '''''new''' ''space'' '''BufferedReader''' and then parentheses.

Inside the parentheses, type the '''object''' of '''InputStreamReader '''which is '''isr'''.

Now, '''isr '''only helps to take the input from the user.

'''BufferedReader''' helps to store the value in the '''BufferedReader object'''.

'''Isr '''passes this value to the '''BufferedReader object''' to store it.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Type,

String str;

int n;

String str1;

System.out.println(“Enter your name”);

str=br.readLine();

System.out.println(“Enter your age”);

| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Now, let us start taking input from the user.

We will first ask the user to enter a '''String'''.

Ask the user to enter the name.

So type, '''System '''''dot'' '''out '''''dot'' '''println''' ''within brackets and double quotes'' '''Enter your name'''.

Before this we will create a variable of '''String''' type.

So type, '''String''' ''space'' '''str'''.

To take the input as '''String''', we will type '''str''' ''equal to'' '''br''' ''dot'' '''readLine''' and parentheses,then semicolon.

The readLine method will read the input from user '''.'''

Now, let us take the input as an '''integer'''.

Ask the user to enter the age.

Type, '''System''' ''dot'' '''out''' ''dot'' '''println''' ''within brackets and double quotes''''' Enter your age'''.

Create a variable of type '''int'''.

So type''' int n '''''semicolon.''

Also, create another variable named '''str1''' of '''String''' type in order to take the input.

So type, '''String str1 '''''semicolon''.

To take the input as '''String,''' type '''str1 '''''equal to '''''br''' ''dot'' '''readLine''' and parentheses, then semicolon.

To convert it into integer datatype, type '''n''' ''equal to'' '''Integer''' ''dot'' '''parseInt''' ''within brackets'' '''str1'''.

Integer is a class and parseInt is its method.

This method converts the argument passed within the bracket into integer.

Now, let us display the output for the''' name''' and '''age'''.

So, type '''System''' ''dot '''''out''' ''dot'' ''println'' ''within brackets and double quotes'' '''The name''' '''is''' ''plus'' '''str''' ''semicolon''.

Next line type, '''System''' ''dot'' '''out''' ''dot'' '''println''' ''within brackets and double quotes'' '''The age is '''''plus'' '''n''' ''semicolon''.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"|
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Now, let us '''Save''', '''Compile''' and '''Run''' this code.

So press''' Control''' and '''F11''' keys simultaneously.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Enter your name

Arya

Enter your age

24

The name is Arya.

The age is 24
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| In the output, you are asked to Enter your name.

Type your name.

Then press '''Enter'''.

Enter your age.

Press '''Enter''' again.

We get the output as follows:

'''The name is Arya.'''

'''The age is 24'''.

This is how we take input from the user.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Summary
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| In this tutorial we have learnt :

* About '''InputStreamReader'''
* About''' BufferedReader'''
* Converting from '''String''' to the desired datatype

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Assignment
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| For self-assessment, take a float, byte and character input from the user and display them on the console.

Take a number as input and divide it by 3. Display the output on the console.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 9

http://spoken-tutorial.org /What\_is\_a\_Spoken\_Tutorial

About the Spoken Tutorial Project
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Watch the video available at the link shown below

It summarises the Spoken Tutorial project

If you do not have good bandwidth, you can download and watch it

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 10

Spoken Tutorial Workshops
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| The Spoken Tutorial Project Team

Conducts workshops using spoken tutorials

Gives certificates to those who pass an online test

For more details, please write to

contact@spoken-tutorial.org

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 11

Acknowledgement
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Spoken Tutorial Project is a part of the Talk to a Teacher project

It is supported by the National Mission on Education through ICT, MHRD, Government of India

More information on this Mission is available at: http://spoken-tutorial.org\NMEICT-Intro

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"|
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| This is Arya Ratish from IIT Bombay.

Thank You for joining.

|}

Java/C2/User-Input/English - Revision history

Chandrika: Created page with ''''Title of script''': '''Taking user input using BufferedReader''' '''Author: Arya Ratish''' '''Keywords: BufferedReader, InputStreamReader, user input, Video tutorial.''' …'