Difference between revisions of "Java/C2/Nested-if/English-timed"
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| By the end of this tutorial you should be able to: | | By the end of this tutorial you should be able to: | ||
− | * Explain '''Nested-If''' Statements and '''Ternary operators''' | + | * Explain '''Nested-If''' Statements and '''Ternary operators''' and |
* Use them in a Java program. | * Use them in a Java program. | ||
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| 00:53 | | 00:53 | ||
− | |In this case, if | + | |In this case, if '''condition1''' is true, then the program checks for '''condition2'''. |
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| 00:59 | | 00:59 | ||
− | |Condition 2 is given using another ''' | + | |Condition 2 is given using another '''if''' statement. |
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| 01:03 | | 01:03 | ||
− | | If | + | | If '''condition2''' is true then the program executes '''Statement or block 1'''. |
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| 01:09 | | 01:09 | ||
− | |Else, it executes Statement or block 2. | + | |Else, it executes '''Statement or block 2'''. |
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| 01:13 | | 01:13 | ||
− | |If | + | |If '''condition1''' is false then the program will not check '''condition2'''. |
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| 01:24 | | 01:24 | ||
− | | Now, | + | | Now, let us try an example to understand that better. |
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| 01:37 | | 01:37 | ||
− | | We shall check if the given number is | + | | We shall check if the given number is an even number or an odd number. |
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| 01:58 | | 01:58 | ||
− | |Now we shall write the '''if''' conditions. | + | |Now, we shall write the '''if''' conditions. |
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| 02:29 | | 02:29 | ||
− | | If the number is not a negative, we check for even and odd. | + | | If the number is not a negative, we check for 'even' and 'odd'. |
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| Next line, type: | | Next line, type: | ||
− | '''else''' open curly bracket . Press Enter. | + | '''else''' open curly bracket. . Press Enter. |
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| 02:42 | | 02:42 | ||
− | |Now, if the execution has come to the '''else''' part | + | |Now, if the execution has come to the '''else''' part, |
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| 02:45 | | 02:45 | ||
− | | | + | |it means that the number is non-negative. |
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| 02:48 | | 02:48 | ||
− | |So we check for odd or even inside this '''else''' part. | + | |So, we check for odd or even inside this '''else''' part. |
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| 03:03 | | 03:03 | ||
− | |'''System.out.println ''' within brackets and double quotes'''Even number''' | + | |'''System.out.println ''' within brackets and double quotes '''Even number'''; |
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| 03:57 | | 03:57 | ||
− | | As we can see, the output is ''' | + | | As we can see, the output is '''Odd number''' as expected. Let us try an even number. |
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| 04:12 | | 04:12 | ||
− | | As we can see, the output is ''' | + | | As we can see, the output is '''Even number''' as expected. |
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| 04:33 | | 04:33 | ||
− | |First let me clean up the '''main method'''. | + | |First, let me clean up the '''main method'''. |
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| 05:18 | | 05:18 | ||
− | |Next line, type: '''if''' within bracket '''n''' modulus '''2 == 0''' open curly brackets Press Enter. | + | |Next line, type: '''if''' within bracket '''n''' modulus '''2 == 0''' open curly brackets. Press Enter. |
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| 05:59 | | 05:59 | ||
− | | So | + | | So, type '''System.out.println''' within brackets '''nHalf''' semicolon''' |
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| 06:11 | | 06:11 | ||
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| 06:31 | | 06:31 | ||
− | |This is when ternary operator makes code simpler. | + | |This is when '''ternary operator''' makes code simpler. |
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| 06:53 | | 06:53 | ||
− | |The | + | |The '''Expression''' is the condition that has to be checked. |
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|06:56 | |06:56 | ||
− | |Operand 1 is the value of the variable. Result if the condition is true. | + | |'''Operand 1''' is the value of the variable. '''Result''' if the condition is true. |
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|07:03 | |07:03 | ||
− | |Operand 2 is the value if the condition is false. | + | |'''Operand 2''' is the value if the condition is false. |
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| 07:17 | | 07:17 | ||
− | |Type: '''nHalf''' equal to '''n''' modulus '''2''' double equal to '''0''' question mark '''n / 2''' colon within brackets '''n + 1''' the whole divided by '''2''' | + | |Type: '''nHalf''' equal to '''n''' modulus '''2''' double equal to '''0''' question mark '''n / 2''' colon within brackets '''n + 1''' the whole divided by '''2''' semicolon. |
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| 08:11 | | 08:11 | ||
− | |In this tutorial we have learnt: | + | |In this tutorial, we have learnt: |
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| 08:13 | | 08:13 | ||
− | |* About '''Nested-If Statements''' and '''Ternary Operator''' | + | |* About '''Nested-If Statements''' and '''Ternary Operator''' and |
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| 08:15 | | 08:15 | ||
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|08:22 | |08:22 | ||
− | |Now take an assignment on | + | |Now take an assignment on |
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| 08:52 | | 08:52 | ||
− | || The Spoken Tutorial Project | + | || The Spoken Tutorial Project team: |
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| 08:54 | | 08:54 | ||
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| 08:57 | | 08:57 | ||
− | ||gives certificates | + | ||gives certificates to those who pass an online test. For more details, please write to '''contact AT spoken HYPHEN tutorial DOT org.''' |
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| 09:17 | | 09:17 | ||
− | ||More information on this mission is available at spoken HYPHEN tutorial DOT org SLASH NMEICT HYPHEN Intro. | + | ||More information on this mission is available at '''spoken HYPHEN tutorial DOT org SLASH NMEICT HYPHEN Intro'''. |
|- | |- |
Revision as of 11:04, 6 April 2015
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 tutorials, 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 look at the syntax for writing the Nested-If statement. |
00:53 | In this case, if condition1 is true, then the program checks for condition2. |
00:59 | Condition 2 is given using another if statement. |
01:03 | If condition2 is true then the program executes Statement or block 1. |
01:09 | Else, it executes Statement or block 2. |
01:13 | If condition1 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 an 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 open curly bracket. . 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 within brackets n modulus 2 double equal to 0 open curly bracket press Enter. |
03:03 | System.out.println within brackets and double quotes Even number; |
03:13 | Then type the else part. else open curly braket, press Enter. |
03:18 | Type: System.out.println within brackets and double quotes Odd number semicolon. |
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 | Now Save 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 semicolon |
05:08 | We will store the number in n and the half number in nHalf |
05:13 | Next line, type: n = 5 semicolon |
05:18 | Next line, type: if within bracket n modulus 2 == 0 open curly brackets. Press Enter. |
05:28 | Type: nHalf = n / 2 semicolon |
05:34 | In the else part, type: within curly brackets nHalf equal to within brackets n+1 the whole divided by 2 semicolon |
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 within brackets nHalf semicolon |
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 is a 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 equal to n modulus 2 double equal to 0 question mark n / 2 colon within brackets n + 1 the whole divided by 2 semicolon. |
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 and |
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 to 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