Difference between revisions of "Java/C2/if-else/English-timed"
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| − | | This script has been contributed by TalentSprint. This is Arya Ratish from IIT Bombay, signing off | + | | This script has been contributed by TalentSprint. This is Arya Ratish from IIT Bombay, signing off. |
Thanks for joining | Thanks for joining | ||
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Revision as of 09:42, 6 April 2015
| 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 conditional 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: 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 space age equal to 20 semicolon. |
| 02:14 | Now, we will write an If statement as follows: |
| 02:18 | Next line, if within brackets 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 semicolon. |
| 02:56 | Here, if age is less than 21, then “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 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 brackets in double quotes The person is Minor semicolon. |
| 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 | So, now let us save 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 displayed the output as “The person is Major”. |
| 05:22 | If…Else If statement: 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 the 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 1 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 then within curly brackets type: 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, if within brackets testScore greater than or equal to 35 AND (&&) testScore less than or equal to 60. Put this whole condition within brackets open curly brackets, press Enter. |
| 08:03 | Type: System dot out dot println within brackets B grade semicolon |
| 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 semicolons 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, |
| 11:32 | watch the video available at the following link. |
| 11:35 | It summarizes the Spoken Tutorial project. |
| 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. |
| 11:47 | * gives certificates for those who pass an online test. For more details, please write to contact AT spoken HYPHEN tutorial DOT org. |
| 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. |
| 12:15 | This script has been contributed by TalentSprint. This is Arya Ratish from IIT Bombay, signing off.
Thanks for joining |
