Difference between revisions of "Java/C2/Nested-if/English-timed"
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Revision as of 12:22, 28 August 2013
| Time | Narration |
| 00:02 | Welcome to the spoken tutorial on Nested-If and Ternary Operator in java. |
| 00:07 | By the end of this tutorial you should be able to:
|
| 00:17 | For this tutorial we are using:
Ubuntu v 11.10, JDK 1.6,and EclipseIDE 3.7.0 |
| 00:27 | To follow this tutorial, you should know, |
| 00:29 | about the usage of relational and logical operators. |
| 00:33 | And if...else control flow statements. |
| 00:36 | If not, for relevant tutorial please visit our website which is as shown. |
| 00:41 | Nested if statements an If statement within another if statement is called a nested-if statement. |
| 00:49 | Now let us locate the syntax for writing the Nested-If statement. |
| 00:53 | In this case, if condition 1 is true, then the program checks for condition 2. |
| 00:59 | Condition 2 is given using another If statement. |
| 01:03 | If condition 2 is true, then the program executes Statement or block 1. |
| 01:09 | Else, it executes Statement or block 2.
|
| 01:13 | If condition 1 is false, then the program will not check condition2. |
| 01:18 | Instead it will directly jump to its else statement i.e. block 3. |
| 01:24 | now Let us try an example to understand that better |
| 01:28 | We have the eclipse IDE and the skeleton required for the rest of the code. |
| 01:32 | We have created a class NesedIfDemo and added the main method to it. |
| 01:37 | We shall check if the given number is a even number or an odd number. |
| 01:42 | we will also handle negative numbers using a nested-if. |
| 01:46 | So inside the main method type |
| 01:49 | int n = minus 5; |
| 01:54 | We have created a variable n to store the negative number. |
| 01:58 | Now we shall write the if conditions. |
| 02:01 | Next line Type |
| 02:02 | if (n < 0) |
| 02:07 | open curly bracket. Press enter |
| 02:10 | System.out.println Within brackets and double quotes (“Negative number”); |
| 02:22 | We first see if the number is a negative number. |
| 02:25 | If yes then we will not check for even and odd. |
| 02:29 | if the number is not a negative, we check for even and odd. |
| 02:34 | Next line Type
else { } Press enter |
| 02:42 | Now if the execution has come to the else part. |
| 02:45 | It means that the number is non negative.
|
| 02:48 | So we check for odd or even inside this else part. |
| 02:52 | Type |
| 02:53 | if (n modules 2 double equal to 0) { Press enter |
| 03:03 | System.out.println(“Even number”);
} else { press enter Type System.out.println(“Odd number”); } |
| 03:29 | So we make sure that negative numbers are not considered for odd or even check. |
| 03:34 | Now let us see the code in action. |
| 03:37 | Save and run the file.As we can see, we get the output as“negative number”. |
| 03:43 | now Let us try a positive number |
| 03:46 | Change n = -5 to n = 5 |
| 03:53 | NowSave and Run the file |
| 03:57 | As we can see, the output is odd number as expected. Let us try an even number |
| 04:04 | Change n = 5 to n = 10. |
| 04:09 | Now Save and run the file |
| 04:12 | As we can see, the output is “even” number as expected. |
| 04:17 | This process of including an if statement inside another, is called nested-if. |
| 04:22 | There is no limit to the amount of nesting. |
| 04:25 | But it is a good practice to not go beyond 3 levels of nesting. |
| 04:31 | Now we shall look at the ternary operator. |
| 04:33 | First let me clean up the Main method. |
| 04:37 | We shall write a program that divides a number by 2. |
| 04:40 | It is a very trivial program but the issue comes in dividing odd numbers. |
| 04:45 | When 7 is divided by 2, we get 3. |
| 04:48 | But what if we want the result to be rounded off. |
| 04:50 | Which means, when 7 is divided by 2, we get 4 and not 3 |
| 04:56 | In simple terms, we need the next number. |
| 04:59 | Let us see how to write such a program. |
| 05:01 | See inside the main method Type int n, nHalf ; |
| 05:08 | We will store the number in n and the half number in nHalf |
| 05:13 | NExt line Type n = 5; |
| 05:18 | NExt line Type if (n % 2 == 0) { Press enter |
| 05:28 | Type nHalf = n / 2;
} else { nHalf = (n + 1) / 2; } |
| 05:50 | We check if the number is even or odd and do the division accordingly. |
| 05:55 | Now Let us add a print statement to see the program in action. |
| 05:59 | So Type System.out.println(nHalf); |
| 06:11 | Now Save and Run the file
|
| 06:14 | As we can see, our objective is met. We get the output as 3 and not 2 |
| 06:21 | But if we notice, all we are doing is, setting the value of a variable depending on a condition.
|
| 06:27 | There is more syntax than logic in our program.
|
| 06:31 | This is when ternary operator makes code simpler. |
| 06:35 | Ternary Operator conditional operator providing results similar to nested-if. |
| 06:40 | It Provides a short syntax and is denoted by a question mark. |
| 06:45 | It Takes three operands at a time. |
| 06:48 | Let us learn about the syntax of Ternary Operator.
|
| 06:53 | The expression is the condition that has to be checked.
|
| 06:56 | Operand 1 is the value of the variable Result if the condition is true.
|
| 07:03 | Operand 2 is the value if the condition is false. |
| 07:09 | Now Let us use it in our program. |
| 07:12 | First let us remove the if-else statement. |
| 07:17 | Type nHalf = n % 2 == 0 ? n / 2 : (n + 1) / 2 semi-colon
|
| 07:41 | This statement reads, |
| 07:43 | if n is even, nHalf is n by 2 ,Otherwise, it is n plus 1 by 2. |
| 07:50 | Let us now see it in action. |
| 07:52 | Save and Runthe file. Press Ctrl S and Ctrl F11 keys |
| 07:59 | As we can see, the output is as expected.
|
| 08:02 | This way, ternary operator reduces clutter in the code and improves readability. |
| 08:09 | We have come to the end of this tutorial. |
| 08:11 | In this tutorial we have learnt: |
| 08:13 | * About Nested-If Statements and Ternary Operator |
| 08:15 | * Usage of Nested-If Statements and Ternary Operator in a Java program |
| 08:22 | Now take an assignment on |
| 08 :23 | Nested-If and Ternary operator. Write java program for the following. |
| 08:28 | * Check whether a number is even and also a multiple of 11 using nested-if. |
| 08:34 | * Identify the largest number among the two given numbers using Ternary operator.
|
| 08:40 | To know more about the Spoken Tutorial project, watch the video available at the following link. |
| 08:45 | It summarizes the spoken-tutorial project.If you do not have good bandwidth, you can download and watch it. |
| 08:52 | The Spoken Tutorial Project Team. |
| 08:54 | Conducts workshops using spoken tutorials and |
| 08:57 | gives certificates for those who pass an online test. For more details, please write to contact AT spoken HYPHEN tutorial DOT org. |
| 09:07 | Spoken Tutorial Project is a part of the Talk to a Teacher project and |
| 09:11 | It is supported by the National Mission on Education through ICT, MHRD, Government of India. |
| 09:17 | More information on this Mission is available at spoken HYPHEN tutorial DOT org SLASH NMEICT HYPHEN Intro |
| 09:26 | This script has been contributed by TalentSprint. This is Arya Ratish from IIT Bombay signing off. Thanks for joining. |
Contributors and Content Editors
Arya Ratish, Devisenan, Krupali, PoojaMoolya, Priyacst, Sandhya.np14, Sneha
