Difference between revisions of "Java/C2/User-Input/English-timed"
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| − | | Welcome to the spoken-tutorial on taking ''' | + | | Welcome to the spoken-tutorial on taking '''User input''' in '''Java''', using '''BufferedReader''' . |
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| − | | To make use of ''BufferedReader'' , we need to '''import''' three | + | | To make use of ''BufferedReader'' , we need to '''import''' three classes from the '''java '''dot''' io package.''' |
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| − | |Once you import the three '''classes | + | |Once you import the three '''classes''', you need to create an object of '''InputStreamReader'''. |
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| − | | Now we will make use of '''BufferedReader '''inside the '''main method'''. | + | | Now, we will make use of '''BufferedReader '''inside the '''main method'''. |
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| − | |'''Exceptions '''are ''' | + | |'''Exceptions '''are '''errors''' which occur in Java when some unexpected circumstances occur. |
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| − | |When we use ''' | + | |When we use ''BufferedReader'', exception error always takes place. |
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| − | |We will learn about | + | |We will learn about ''Exception Handling'' in the coming tutorials. |
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| − | |So, type: '''BufferedReader br''' equal to '''new''' space '''BufferedReader''' and then parentheses. | + | |So, type: '''BufferedReader space br''' equal to '''new''' space '''BufferedReader''' and then parentheses. |
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| − | |'''Isr '''passes this value to the '''BufferedReader | + | |'''Isr '''passes this value to the '''BufferedReader''' object to store it. |
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| − | |Thus we know how to take an input from the user. | + | |Thus, we know how to take an input from the user. |
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| − | |More information on this mission is available at: http://spoken-tutorial.org\NMEICT-Intro. | + | |More information on this mission is available at: |
| + | http://spoken-tutorial.org\NMEICT-Intro. | ||
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Revision as of 17:38, 8 April 2015
| 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 about the data types 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 11.10 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 in java 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 data type. |
| 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 BufferedReader. |
| 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 semicolon. |
| 02:13 | 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 space 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 takes 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 java which allows us to take the user input . |
| 04:01 | System dot in tells 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 space 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 name and then semicolon. |
| 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 type int. |
| 06:01 | So, type: int n semicolon. |
| 06:05 | Ask the user to enter his age. |
| 06:08 | So, type: System dot out dotprintln 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 with capital I dot parseInt, capital I within brackets str1 semicolon. |
| 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 age is plus n and then semicolon. |
| 07:50 | Now, Save the file, press Ctrl, S keys. 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 here 20 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 data type. |
| 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 summarizes 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: |
| 09:36 | This is Arya Ratish from IIT Bombay.
Thank You for joining. |
