Difference between revisions of "Java/C2/Switch-Case/English-timed"

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|  00:02
 
|  00:02
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|  Welcome to the spoken tutorial on '''Switch Case in Java'''.
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|  Welcome to the spoken tutorial on '''Switch Case''' in Java.
  
 
|-
 
|-
 
|  00:06
 
|  00:06
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|  In this tutorial, you will learn how to use the '''switch case construct in Java'''
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|  In this tutorial, you will learn how to use the '''switch case construct''' in Java.
  
 
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|-
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|  00:21  
 
|  00:21  
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| For this tutorial, you should have knowledge of if else statement in Java.
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| For this tutorial, you should have knowledge of '''if else''' statement in Java.
  
 
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|-
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|-
 
|-
 
|  00:57
 
|  00:57
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|  Inside the main method, we will create a '''variable day''' of type '''int'''.
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|  Inside the '''main method''', we will create a variable '''day''' of '''type''' '''int'''.
  
 
|-
 
|-
 
|  01:02
 
|  01:02
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| So type inside the main method''' int day '''and we can give it a value '''equal to''' '''3''' semi-colon.
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| So, type inside the '''main method''' '''int day''' and we can give it a value equal to '''3''' semi-colon.
  
 
|-
 
|-
 
|  01:12
 
|  01:12
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| Now, let us create a '''variable dName''' of type '''String.'''
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| Now, let us create a variable '''dName''' of '''type String.'''
  
 
|-
 
|-
 
|  01:18
 
|  01:18
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| String dName   we can linitialize it to null.  
+
| String '''dName''' we can initialize it to null.  
  
 
|-
 
|-
 
| 01:25
 
| 01:25
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| Here '''dName '''is a '''variable '''to hold the names of the days of a week.
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| Here, '''dName''' is a '''variable''' to hold the names of the days of a week.
  
 
|-
 
|-
 
|  01:34
 
|  01:34
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|  '''day''' stores the '''day number'''.
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|  '''day''' stores the day number.
  
 
|-
 
|-
 
|  01:36
 
|  01:36
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| Now, we will type the '''switch case statement.'''So next line type
+
| Now, we will type the '''switch case''' statement. So, next line, type:
  
 
|-
 
|-
 
|  01:43
 
|  01:43
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|   '''switch '''within brackets''' day , '''then open curly brackets... Press enter
+
| '''switch''' within brackets '''day''' then open curly brackets Press Enter.
  
 
|-
 
|-
 
|  01:52
 
|  01:52
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|  This statement defines which variable is under consideration for the cases.
+
|  This statement defines which variable is under consideration for the '''cases'''.
  
 
|-
 
|-
 
|  01:59
 
|  01:59
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|  Next line '''type '''
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|  Next line, type:
  
 
|-
 
|-
 
|  02:01
 
|  02:01
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| '''case 0 '''''colon''
+
| '''case 0''' colon  
  
 
|-
 
|-
 
|  02:04
 
|  02:04
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|Next line '''dName '''''equal to within double quotes''''' Sunday '''''semicolon''
+
|Next line, '''dName '''equal to within double quotes '''Sunday''' semicolon.
  
 
|-
 
|-
 
|  02:14
 
|  02:14
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| Then type Next line'''break '''''  
+
| Then type: Next line '''break'''  
  
 
|-
 
|-
 
|  02:17
 
|  02:17
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| This statement says that if the   day is 0,  then     '''dName''' must be set to '''Sunday.'''
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| This statement says that if the day is 0 then '''dName''' must be set to '''Sunday'''.
  
 
|-
 
|-
 
|  02:26
 
|  02:26
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| Note that a '''break''' statement must be used at the end of each case.
+
| Note that a '''break''' statement must be used at the end of each '''case'''.
  
 
|-
 
|-
 
|  02:31
 
|  02:31
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| without the break statement, the switch-case functions in a complex fashion.
+
| without the '''break''' statement, the '''switch-case''' functions in a complex fashion.
  
 
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|-
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|-
 
|-
 
|  02:40
 
|  02:40
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|   Similarly, let us type the remaining cases.
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| Similarly, let us type the remaining '''cases'''.
  
 
|-
 
|-
 
| 02:45
 
| 02:45
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| Next line type '''case 1 '''''colon''
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|Next line, type: '''case 1''' colon.
  
 
|-
 
|-
 
| 02:50
 
| 02:50
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| next line '''dName '''''equal to within double quotes''''' Monday '''''semicolon''
+
| Next line, '''dName''' equal to within double quotes '''Monday''' semicolon  
  
 
|-
 
|-
 
| 02:56
 
| 02:56
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| Next line type '''break '''
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| Next line, type '''break'''
  
 
|-
 
|-
 
| 02:58
 
| 02:58
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|Then type '''case 2 '''''colon''
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|Then type: '''case 2''' colon  
  
 
|-
 
|-
 
| 03:01
 
| 03:01
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|Next line '''dName '''''equal to ''''' Tuesday ''''' then semicolon''
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|Next line, '''dName''' equal to ''' Tuesday''' then semicolon  
  
 
|-
 
|-
 
| 03:06
 
| 03:06
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| Next line type '''break '''
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| Next line, type '''break'''
  
 
|-
 
|-
 
| 03:08
 
| 03:08
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| Then next line '''case 3 '''''colon''
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| Then next line, '''case 3''' colon  
  
 
|-
 
|-
 
| 03:12
 
| 03:12
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| Next line type '''dName '''''equal to within double quotes''''' Wednesday ''''' then semicolon''
+
| Next line, type: '''dName''' equal to within double quotes '''Wednesday''' then semicolon  
  
 
|-
 
|-
 
| 03:18
 
| 03:18
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|Next line type '''break ''''
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|Next line, type '''break'''  
  
 
|-
 
|-
 
| 03:20
 
| 03:20
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|  Then'''case 4 '''''colon''
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|  Then '''case 4''' colon  
  
 
|-
 
|-
 
| 03:24
 
| 03:24
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|Next line '''dName '''''equal to within double quotes''''' Thursday ''''' then semicolon''
+
|Next line, '''dName''' equal to within double quotes '''Thursday''' then semicolon
  
 
|-
 
|-
 
| 03:32
 
| 03:32
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| Then'''break '''
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| Then '''break '''.
  
 
|-
 
|-
 
| 03:24
 
| 03:24
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| Then next line type'''case 5 '''''colon''
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| Then next line, type: '''case 5''' colon  
  
 
|-
 
|-
 
| 03:37
 
| 03:37
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| '''dName '''''equal to within double quotes''''' Friday '''''then semicolon''
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| '''dName''' equal to within double quotes '''Friday''' then semicolon.
  
 
|-
 
|-
 
| 03:41
 
| 03:41
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| Then'''break '''  
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| Then '''break'''.
 
|-
 
|-
 
| 03:43
 
| 03:43
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|Then ''' case 6 '''''colon''
+
|Then '''case 6''' colon  
  
 
|-
 
|-
 
| 03:47
 
| 03:47
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|Next line type '''dName '''''equal to within double quotes''''' Saturday ''''' then semicolon''
+
|Next line, type: '''dName''' equal to within double quotes '''Saturday''' then semicolon  
  
 
|-
 
|-
 
| 03:55
 
| 03:55
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|Then type '''break ''' semicolon
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|Then type: '''break''' semicolon.
 
   
 
   
 
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|-
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|-
 
|-
 
| 04:03
 
| 04:03
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|   now Let us add a print statement and see the code in action.
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| Now Let us add a print statement and see the code in action.
  
 
|-
 
|-
 
|  04:07
 
|  04:07
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| So next line Type '''System '''''dot '''''out '''''dot '''''println '''''within brackets '''''dName ''''' then semicolon.''
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| So, next line, type: '''System ''' dot '''out''' dot '''println''' within brackets '''dName''' then semicolon.  
  
 
|-
 
|-
 
|  04:16
 
|  04:16
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| Now '''Save''' and run the file.
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| Now '''Save''' and '''run''' the file.
  
 
|-
 
|-
 
|  04:20
 
|  04:20
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| Now press Ctrl S and Ctrl F11 keys
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| Now press '''Ctrl S''' and '''Ctrl F11''' keys.
  
 
|-
 
|-
 
|  04:25
 
|  04:25
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| we get the output as '''Wednesday'''which is corresponding to the case '''3.'''
+
| We get the output as: '''Wednesday''' which is corresponding to the '''case 3.'''
  
 
|-
 
|-
 
|  04:31
 
|  04:31
−
| Now Let us change the value of the  day and see the result
+
| Now Let us change the value of the  day and see the result.
  
 
|-
 
|-
 
| 04:35
 
| 04:35
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|  SoChange '''3''' to '''0'''
+
|  So change '''3''' to '''0'''.
  
 
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|-
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|-
 
|-
 
|  04:46
 
|  04:46
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| Now, what if there is no '''case''' corresponding to the value. So Let us see that.
+
| Now, what if there is no '''case''' corresponding to the value. So, let us see that.
  
 
|-
 
|-

Revision as of 20:06, 25 March 2015

Time Narration
00:02 Welcome to the spoken tutorial on Switch Case in Java.
00:06 In this tutorial, you will learn how to use the switch case construct in Java.
00:11 For this tutorial, we are using
  • Ubuntu v 11.10
  • JDK 1.6 and
  • Eclipse 3.7.0
00:21 For this tutorial, you should have knowledge of if else statement in Java.
00:25 If not, please go through the tutorials on these topics available at our website which is as shown [1]
00:32 A switch case is used to perform actions based on the value of a variable.
00:39 Here is the syntax for a switch case statement.
00:44 Let us use it now.
00:47 I already have Eclipse opened.
00:49 I have created a class named SwitchCaseDemo.
00:53 Now Let us add some variables.
00:57 Inside the main method, we will create a variable day of type int.
01:02 So, type inside the main method int day and we can give it a value equal to 3 semi-colon.
01:12 Now, let us create a variable dName of type String.
01:18 String dName we can initialize it to null.
01:25 Here, dName is a variable to hold the names of the days of a week.
01:34 day stores the day number.
01:36 Now, we will type the switch case statement. So, next line, type:
01:43 switch within brackets day then open curly brackets Press Enter.
01:52 This statement defines which variable is under consideration for the cases.
01:59 Next line, type:
02:01 case 0 colon
02:04 Next line, dName equal to within double quotes Sunday semicolon.
02:14 Then type: Next line break
02:17 This statement says that if the day is 0 then dName must be set to Sunday.
02:26 Note that a break statement must be used at the end of each case.
02:31 without the break statement, the switch-case functions in a complex fashion.
02:35 It will be explained in subsequent part of the tutorial.
02:40 Similarly, let us type the remaining cases.
02:45 Next line, type: case 1 colon.
02:50 Next line, dName equal to within double quotes Monday semicolon
02:56 Next line, type break
02:58 Then type: case 2 colon
03:01 Next line, dName equal to Tuesday then semicolon
03:06 Next line, type break
03:08 Then next line, case 3 colon
03:12 Next line, type: dName equal to within double quotes Wednesday then semicolon
03:18 Next line, type break
03:20 Then case 4 colon
03:24 Next line, dName equal to within double quotes Thursday then semicolon
03:32 Then break .
03:24 Then next line, type: case 5 colon
03:37 dName equal to within double quotes Friday then semicolon.
03:41 Then break.
03:43 Then case 6 colon
03:47 Next line, type: dName equal to within double quotes Saturday then semicolon
03:55 Then type: break semicolon.
03:59 Then close the brackets.
04:03 Now Let us add a print statement and see the code in action.
04:07 So, next line, type: System dot out dot println within brackets dName then semicolon.
04:16 Now Save and run the file.
04:20 Now press Ctrl S and Ctrl F11 keys.
04:25 We get the output as: Wednesday which is corresponding to the case 3.
04:31 Now Let us change the value of the day and see the result.
04:35 So change 3 to 0.
04:38 Now Save and Run that file.
04:40 As we can see, the output is Sunday corresponding to the case 0.
04:46 Now, what if there is no case corresponding to the value. So, let us see that.
04 :52 Change day equal to -1 Save and run the file.
04:58 As we can see, there is no output.
05:01 But it would be better if we could have a case for all other values.
05:06 That is done by using the default keyword.
05:09 So, after the last case, type:
05:12 default colon
05:14 Next line, dName equal to within double quotes Wrong Choice then semicolon
05:24 Next line, break semicolon
05:27 We do not say case default;
05:30 Note that we simply use the keyword default.
05:34 Now, let us run the code. So save and run the file.
05:38 As we can see, the default case is executed and the required message Wrong choice is printed.
05:45 Let us try with another random value.
05:48 Change -1 to 15.
05:51 As we can see, again the default case is executed.
05:57 Now, let us see what happens if we remove the break statement.
06:01 So, Let us change day = 15 to day = 4,
06:07 remove the corresponding break statement for day =4.
06:12 Now Save and run.
06:15 Although the case is 4, we get the output as Friday and not Thursday.
06:20 because of the way switch case works.
06:24 First the value of day is compared with 0.
06:29 Then with 1, then with 2 and so on with all the possible cases.
06:34 When a match is found, it executes all the case from the match onwards.
06:42 In our case, it executed case 5 after case 4.
06:47 Then it stops because of the break statement in case 5.
06:53 To avoid that, we need to add a break statement in each case.
06:57 Let us now add the break statement we have removed.
07:00 So, type: break semicolon.
07:05 Now let us run the code.
07:08 As we can see, now only case 4 is executed.
07:13 As a rule, remember to use a break statement in every case, to avoid errors.
07:20 We have come to the end of this tutorial.
07:22 In this tutorial, we have learnt how to use switch case construct and how to use break statement.
07:30 As an assignment, write a program that has a name and gender as a variable. Use a switch case statement that prints “Hello Mr....” for males and “Hello Ms...” for females.
07:44 To know more about the Spoken Tutorial project, watch the video available at the following link, it summarizes the spoken-tutorial project.
07:53 If you do not have good bandwidth, you can download and watch it.
07:58 The Spoken Tutorial Project Team. Conducts workshops using spoken tutorials and gives certificates for those who pass an online test.
08:06 For more details, please write to contact AT spoken HYPHEN tutorial DOT org.
08:12 Spoken Tutorial Project is a part of the Talk to a Teacher project and it is supported by the
08:17 National Mission on Education through ICT, MHRD, Government of India.
08:22 More information on this mission is available at spoken HYPHEN tutorial DOT org SLASH NMEICT HYPHEN Intro.
08:31 This tutorial has been contributed by TalentSprint. Thanks for joining.

Contributors and Content Editors

Gaurav, PoojaMoolya, Sandhya.np14, Sneha

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