Difference between revisions of "Java/C2/if-else/English-timed"
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Revision as of 12:55, 9 July 2014
| Time | Narration |
| 00:02 | Welcome to the spoken tutorial on If else constructs in java. |
| 00:07 | In this tutorial we will learn: |
| 00:09 | * About conditional statements |
| 00:11 | * types of conditional statements and |
| 00:13 | * How to use conditional statements in Java programs |
| 00:18 | For this tutorial we are using:
Ubuntu v 11.10 JDK 1.6 and Eclipse 3.7.0 |
| 00:27 | To follow this tutorial you should have knowledge of using |
| 00:31 | * Arithmetic, Relational and Logical operators in Java |
| 00:35 | If not, for relevant tutorials please visit our website which is as shown. |
| 00:42 | Conditional statements You may have to perform different actions for different decisions in your code.
|
| 00:48 | In such cases you can use conditional statements.
|
| 00:52 | A conditiona statement helps to control the flow of execution of a program.
|
| 00:57 | In Java we have the following conditional statements: |
| 01:01 | * If statement ; |
| 01:02 | * If...Else statement ; |
| 01:03 | * If...Else if statement ; |
| 01:05 | * Nested If statement |
| 01:06 | * Switch statement |
| 01:08 | In this tutorial, we will learn about If, If...Else and If...Else If statements in detail. |
| 01:15 | If statement ;is used to execute a block of statements based on a condition.
|
| 01:22 | It is called a single conditional statement.
|
| 01:26 | Syntax for If statement ;'
|
| 01:28 | In the if statement, if the condition is true, the block is executed.
|
| 01:34 | If the condition is false, the block is skipped and it is not executed.
|
| 01:40 | now Let us look at an example to understand how the If Statement can be used.
|
| 01:45 | So Let us switch to eclipse.
|
| 01:48 | We will write a program to identify whether a person is Minor.
|
| 01:53 | I have already created a class Person.
|
| 01:56 | Now, inside the main method let us declare a variable ‘age’ of type int. |
| 02:02 | So type inside the main method int age is equal to 20 semi-colom. |
| 02:14 | Now, we will write an If statement as follows:
|
| 02:18 | Next line if within bracket age < 21 open curly brackets. Press enter
|
| 02:30 | Here, we are checking if age is less than 21.
|
| 02:34 | Whatever is inside the brackets belongs to the if block.
|
| 02:38 | So Inside the brackets type
|
| 02:41 | System dot out dot println within brackets and double quotes The person is Minor semi-colon.
|
| 02:56 | Here, if age is less than 21, than “The person is minor” will be displayed.
|
| 03:03 | So save and run the file. |
| 03:08 | We get the output as follows. The person is minor
|
| 03:14 | In this case, the person's age is 20, which is less than 21. |
| 03:20 | So, we got the output as “The person is minor”.
|
| 03:24 | Now, we will learn about if...else statement.
|
| 03:27 | If...Else statement is used to execute alternative statements.
|
| 03:31 | These are based on a single condition.
|
| 03:34 | Let us look at the syntax for writing If…Else statement.
|
| 03:38 | If the condition is True, the statement or block of code is executed..
|
| 03:44 | Else it executes another statement or block of code. |
| 03:49 | We will now see how the If…else statement ;can be used in a program. |
| 03:54 | So let us switch to the eclipse. |
| 03:57 | we will now write a program to identify whether the person is Minor or Major.
|
| 04:03 | So inside the Main method type; int age is equal to 25
|
| 04:12 | then if within brackets age greater than 21, |
| 04:19 | within curly brackets type System dot out dot println within brackets The person is Major.
|
| 04:28 | Then type,next line |
| 04:32 | else within curly brackets type |
| 04:38 | System dot out dot println within bracketsin double quotes The person is Minor semi-colon.
|
| 04:51 | Here, if age' is less than 21, “' The person is Minor” will be displayed.
|
| 04:58 | Else the “The person is Major” will be displayed.
|
| 05:02 | See now Let ussave and run the program. |
| 05:07 | We get the output as the person is major |
| 05:11 | Here, the person's age is 25, which is greater than 21.
|
| 05:17 | Therefore the program display the output as “The person is Major”.
|
| 05:22 | If…Else If statement is used to execute various set of statements.
|
| 05:29 | These are based on the two given conditions.
|
| 05:33 | You can also add more conditions based on your requirement.
|
| 05:38 | It is also called as branching or decision making statement.
|
| 05:43 | Now Let us look at the syntax for writing If…Else If statement.
|
| 05:48 | If statement initially checks for condition 1.
|
| 05:53 | If condition 1 is true, it executes the statement or block code .
|
| 05:59 | Else it again checks for condition 2.
|
| 06:02 | If condition 2 is true, it executes statement or block 2.
|
| 06:09 | Else it executes statement 3 or block code 3.
|
| 06:13 | In this way, we can extend the code by If…Else blocks.
|
| 06:17 | These blocks can have multiple conditions.
|
| 06:20 | The corresponding code will get executed until it finds the true condition.
|
| 06:25 | If all the conditions are false, it will execute the final Else section. |
| 06:30 | We will see how the If…Else If statement ;can be used in a program.
|
| 06:35 | So switch to Eclipse.
|
| 06:37 | I have already created a class named Student.
|
| 06:40 | Let us write a program to identify grade of a student.
|
| 06:44 | This is done based on the score percentage.
|
| 06:47 | So inside the Main method, type int space testScore equal to 70 semicolon.
|
| 06:58 | The input variable named ‘testScore’ is used to get the score percentage.
|
| 07:05 | Next line type if within brackets testScore less than 35, within curly brackets System dot out dot println within brackets and double quotes C grade semicolon.
|
| 07:28 | If the testScore is less than 35, then the program displays "C Grade".
|
| 07:34 | Next line type else
|
| 07:37 | next line type if within brackets testScore greater than or equal to 35 and testScore less than or equal to 60.Put the soul condition within brackets open curly brackets press enter. |
| 08:03 | Type System dot out dot println within brackets B grade semi-colomn |
| 08:13 | Here, the program will check for the second condition in the Else If section. |
| 08:18 | If the testScore is between 35 and 60 then the program displays "B Grade".
|
| 08:24 | Next line type else within brackets type System dot out dot println within brackets and double quotes A grade semicolon.
|
| 08:42 | So Finally, if both the conditions are False, the program displays “A Grade".
|
| 08:48 | Now, let us save and run this code.
|
| 08:51 | We get the output as A Grade |
| 08:55 | In this program, the student’s testScore is 70 .
|
| 09:00 | So the output will be displayed as “A Grade”. |
| 09:02 | Now Let us change the testScore to 55.
|
| 09:07 | Now, save and run this program. |
| 09:10 | In this case, the output will be displayed as “B Grade”. |
| 09:16 | We can also increase the number of conditions.
|
| 09:19 | Let us add one more condition after the “B grade” output section.
|
| 09:23 | So type here,
Else, Next line if within brackets testScore greater than or equal to 60 and testScore less than or equal to 70.
|
| 09:47 | Open curly brackets press enter System dot out dot println within brackets and double quotes O grade semicolon.
|
| 10:01 | Here if the testScore is between 60 and 70 the program will display "O Grade".
|
| 10:07 | Now, change the testScore of the student to 70.
|
| 10:12 | Now, save and run the file.
|
| 10:15 | We get the output as follows.
|
| 10:17 | The program will display the output as “O grade”.
|
| 10:20 | It is not “A grade” as it displayed before.
|
| 10:23 | The program will display “A grade” for the testScore greater than 70. |
| 10:28 | While coding conditional structures: |
| 10:30 | * Always remember to add a semicolon while terminating a statement. |
| 10:35 | * But don’t add semi-colons after the condition. |
| 10:40 | * Add the block of code within curly brackets |
| 10:43 | * Curly braces are optional if the block contains a single statement. |
| 10:49 | We have come to the end of this tutorial. |
| 10:51 | In this tutorial, |
| 10:53 | We have Explained conditional statements |
| 10:56 | * Listed the types of conditional statements |
| 10:59 | * Used conditional statements: if, if...else and if...else if in Java programs. |
| 11:04 | Now take an assignment on writing java programs using conditional statements: if, if...else and if...else if statements.
|
| 11:12 | * Write a java program to compare two values using if statement. |
| 11:17 | * Write a java program to check whether the given number is even or odd.
Hint : use if...else statement. |
| 11:23 | * Write a java program to find the biggest number among the three numbers.
Hint : use if...else if statement.
|
| 11:29 | To know more about the Spoken Tutorial project,
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| 11:32 | watch the video available at the following link. |
| 11:35 | It s ummarizes the Spoken Tutorial project.
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| 11:38 | If you do not have good bandwidth, you can download and watch it |
| 11:42 | The Spoken Tutorial Project Team |
| 11:44 | * Conducts workshops using spoken tutorials |
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| 11:56 | Spoken Tutorial Project is a part of the Talk to a Teacher project |
| 12:00 | It is supported by the National Mission on Education through ICT, MHRD, Government of India. |
| 12:06 | More information on this Mission is available at spoken HYPHEN tutorial DOT org SLASH NMEICT HYPHEN Intro
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| 12:15 | This script has been contributed by TalentSprint. This is Arya. Ratish from IIT Bombay signing off
Thanks for joining
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