Difference between revisions of "Java/C2/User-Input/English-timed"
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| − | | Now, '''Save''' the file, press '''Ctrl | + | | Now, '''Save''' the file, press '''Ctrl, S'''keys. Now let us run the program |
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Revision as of 15:21, 26 June 2013
| Time' | Narration |
| 00:02 | Welcome to the spoken-tutorial on Taking user input in Java using BufferedReader . |
| 00:09 | In this tutorial we will learn: |
| 00:11 | To take user input in Java |
| 00:13 | About InputStreamReader and BufferedReader
|
| 00:17 | To follow this tutorial you must know: |
| 00:19 | how to write, compile and run a simple java program in Eclipse |
| 00:24 | You must also know the about the datatypes in Java |
| 00:27 | If not, please refer to the spoken tutorial on these topics available at spoken hyphen tutorial dot org.
|
| 00:35 | Here, I am using,
Ubuntu v 11.04 JDK 1.6 and Eclipse IDE 3.7.0 |
| 00:44 | Now, we will learn what a BufferedReader is. |
| 00:48 | It is a class which is used to read text from an input stream. |
| 00:53 | It provides efficient way to read array of characters and lines.
|
| 00:59 | To make use of BufferedReader , we need to import three classes' from the java dot io package. |
| 01:05 | These three classes are:
|
| 01:12 | We will learn about packages and how to import classes in the coming tutorials. |
| 01:18 | Now how is the input taken. |
| 01:21 | All the input that we take from the user will be in the form of String. |
| 01:26 | It has to be then typecasted or converted to the particular datatype. |
| 01:31 | We will see that while we write our program to take the user input. |
| 01:35 | Now, let us see the syntax to implement BufferedReader. |
| 01:39 | Once you import the three classes, you need to create an object of InputStreamReader. |
| 01:45 | You also need to create an object of BufferedReasder. |
| 01:49 | We will learn about this in detail, when we write our program. |
| 01:54 | So, let us switch to Eclipse. |
| 01:56 | I have already opened a class named InputBufferedReader. |
| 02:00 | We will begin with importing the java.io package.
|
| 02:04 | So type, before the class import space java dot io dot star semi colon. |
| 02:14 | This will import the classes InputStreamReader, BufferedReader and IOException.
|
| 02:20 | Now We will make use of BufferedReader inside the main method. |
| 02:25 | We need to throw an IOException in whatever method we use the BufferedReader. |
| 02:31 | So right after the main method type throws IOException. |
| 02:42 | Now, what does this mean? |
| 02:45 | Exceptions are errors which occur in Java when some unexpected circumstances occur. |
| 02:52 | To prevent Exception errors we make use of throws keyword. |
| 02:57 | Throws is a keyword which is used during Exception handling. |
| 03:00 | It is used whenever we know that Exception error will definitely occur. |
| 03:05 | When we use BufferedReader, exception error always take place. |
| 03:10 | To prevent Exception errors from taking place we make use of throws IOException. |
| 03:16 | We will learn about Exception Handling in the coming tutorials. |
| 03:20 | Now, we will create an object of InputStreamReader. |
| 03:24 | For that, inside the main method type InputStreamReader space isr equalto new space InputStreamReader parentheses. |
| 03:44 | Within parentheses, type System dot in and then semicolon. |
| 03:52 | InputStreamReader is a class in javawhich allows us to take the user input . |
| 04:01 | System dot intells the java compiler to take the input from the user using keyboard. |
| 04:10 | The input that System dot in takes is stored in the object of InputStreamReader for sometime. |
| 04:17 | After this we create an object of BufferedReader. |
| 04:22 | So type, BufferedReader br equal to new space BufferedReader and then parentheses. |
| 04:36 | Inside the parentheses, type the object of InputStreamReader which is isr. |
| 04:43 | Now, isr only helps to take the input from the user. |
| 04:48 | BufferedReader helps to store the value in the BufferedReader object. |
| 04:54 | Isr passes this value to the BufferedReader object to store it. |
| 05:01 | Now, let us start taking input from the user. |
| 05:06 | We will first ask the user to enter a String. So create a variable of String type
|
| 05:14 | Type, String space str semicolon |
| 05:19 | Now ask the user to enter his name. |
| 05:23 | So type, System dot out dot println within brackets and double quotes Enter your nameand thensemicolon. |
| 05:33 | To take the input as String we will type. |
| 05:37 | str equal to br dot readLine parentheses and then semicolon. |
| 05:45 | The readLine method will read the input from the user . |
| 05:51 | Now, let us take the input as an integer. Create a variable of typeint. |
| 06:01 | So type int n semicolon. |
| 06:05 | Ask the user to enter his age. |
| 06:08 | So Type, System dot out dot println within brackets and double quotes Enter your age semicolon.
|
| 06:21 | Also, create another variable named str1 of String type in order to take the input.
|
| 06:31 | Now to take the input as String, type str1 equal to br dot readLine parentheses and then semicolon. |
| 06:45 | To convert it into integer datatype, type n equal to Integer dot parseInt within brackets str1semicolon |
| 07:05 | Integer is a class and parseInt is its method. |
| 07:11 | This method converts the argument passed within the bracket into integer. |
| 07:18 | Now, let us display the output for name and age. |
| 07:22 | So, type System dot out dot println within brackets and double quotes The name is plus str semicolon. |
| 07:38 | Next line type, System dot out dot println The ages plus n and thensemicolon. |
| 07:50 | Now, Save the file, press Ctrl, Skeys. Now let us run the program |
| 07:55 | So press Control and F11 keys. |
| 08:00 | In the output, you are asked to Enter your name. |
| 08:03 | So type your name. I will type here Ramu press Enter. |
| 08:08 | You will be asked to enter your age. |
| 08:11 | I will type here20 and then press Enter |
| 08:13 | We get the output as : |
| 08:15 | The name is Ramu |
| 08:16 | And The age is 20. |
| 08:18 | Thus we know how to take an input from the user. |
| 08:24 | In this tutorial we have learnt : |
| 08:26 | About InputStreamReader |
| 08:28 | About BufferedReader |
| 08:29 | And Converting from String to the desired datatype
|
| 08:33 | For self-assessment, take a float, byte and character input from the user and then display the output |
| 08:42 | Also take a number as input and divide it by 3 then Display the output on the console. |
| 08:49 | To know more about the spoken tutorial project;Watch the video available at the following link |
| 08:54 | It summarises the Spoken Tutorial project |
| 08:57 | If you do not have good bandwidth, you can download and watch it |
| 09:02 | The Spoken Tutorial Project Team |
| 09:04 | Conducts workshops using spoken tutorials |
| 09:07 | Gives certificates to those who pass an online test |
| 09:11 | For more details, please write to contact@spoken-tutorial.org |
| 09:18 | Spoken Tutorial Project is a part of the Talk to a Teacher project |
| 09:21 | It is supported by the National Mission on Education through ICT, MHRD, Government of India |
| 09:27 | More information on this Mission is available at: http://spoken-tutorial.org\NMEICT-Intro |
| 09:36 | This is Arya Ratish from IIT Bombay.
Thank You for joining. |
