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

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(Created page with ''''Title of script''': Switch Case in Java '''Author''': TalentSprint '''Keywords: '''case, switch, conditions, video tutorial {| style="border-spacing:0;" | style="border:0…')
 
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| style="border:0.035cm solid #000000;padding:0.097cm;"| For this tutorial we are using  
 
| style="border:0.035cm solid #000000;padding:0.097cm;"| For this tutorial we are using  
  
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* '''Ubuntu 11.10'''
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* '''Ubuntu v 11.10'''
 
* '''JDK 1.6''' and  
 
* '''JDK 1.6''' and  
 
* '''Eclipse 3.7.0'''
 
* '''Eclipse 3.7.0'''
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If not, please go through the tutorials on these topics available at our website [http://spoken-tuitorial.org/ http][http://spoken-tuitorial.org/ ://][http://spoken-tuitorial.org/ spoken][http://spoken-tuitorial.org/ -][http://spoken-tuitorial.org/ tutorial][http://spoken-tuitorial.org/ .][http://spoken-tuitorial.org/ org]
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If not, please go through the tutorials on these topics available at our website which is as shown [http://spoken-tuitorial.org/ http][http://spoken-tuitorial.org/ ://][http://spoken-tuitorial.org/ spoken][http://spoken-tuitorial.org/ -][http://spoken-tuitorial.org/ tutorial][http://spoken-tuitorial.org/ .][http://spoken-tuitorial.org/ org]
  
 
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'''switch case'''
 
'''switch case'''
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| style="border:0.035cm solid #000000;padding:0.097cm;"| The switch case is used to perform actions based on the value of a variable.
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| style="border:0.035cm solid #000000;padding:0.097cm;"| A switch case is used to perform actions based on the value of a variable.
  
  
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Let us add some variables.
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Now Let us add some variables.
  
 
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Highlight day and dName when you explain.
 
Highlight day and dName when you explain.
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| style="border:0.035cm solid #000000;padding:0.097cm;"| Inside the main, we will create a '''variable day''' of type '''int'''.
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| style="border:0.035cm solid #000000;padding:0.097cm;"| Inside the main method, we will create a '''variable day''' of type '''int'''.
  
  
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So type''' int day '''and we can give it a value '''equal to''' '''3'''.
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So type inside the main  method''' int day '''and we can give it a value '''equal to''' '''3''' semi-colon.
  
  
 
Now, let us create a '''variable dName''' of type '''String.'''
 
Now, let us create a '''variable dName''' of type '''String.'''
  
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String dane we shall initialize
  
 
Then initialize it to null.
 
Then initialize it to null.

Revision as of 09:25, 9 May 2013

Title of script: Switch Case in Java

Author: TalentSprint

Keywords: case, switch, conditions, video tutorial


Visual Cue Description
Slide 1

Welcome

Welcome to the spoken tutorial on Switch case in Java.
Slide 2

Learning Outcomes

In this tutorial, you will learn how to use the switch case construct in Java
Slide 3

Tools Used

For this tutorial we are using
  • Ubuntu v 11.10
  • JDK 1.6 and
  • Eclipse 3.7.0


Slide 4

Prerequisites

For this tutorial, you should have knowledge of if else statement in Java.


If not, please go through the tutorials on these topics available at our website which is as shown http://spoken-tutorial.org

Slide 5

switch case

A switch case is used to perform actions based on the value of a variable.


Here is the syntax for a switch case statement.


Let us use it now.

Minimize Slides and open Eclipse

Eclipse should contain the following code

public class SwitchCaseDemo{

public static void main(String[] args){

}

}

I already have Eclipse opened.


I have created a class named SwitchCaseDemo.


Now Let us add some variables.

Inside the main, type

int day = 3;

String dName = “”;


Highlight day and dName when you explain.

Inside the main method, we will create a variable day of type int.


So type inside the main method int day and we can give it a value equal to 3 semi-colon.


Now, let us create a variable dName of type String.

String dane we shall initialize

Then initialize it to null.


Here dName is a variable to hold the names of the days of a week.


day stores the day number.

Now, we will type the switch case statement.


So type switch within brackets day , then open curly brackets...



Highlight switch(day) This statement defines which variable is under consideration for the cases.
Type


switch(day) {

case 0:

dName = “Sunday”;

break;

}

Next line type


case 0 colon

dName equal to within double quotes Sunday semicolon

Then type break semicolon.


This statement says that if the value of day is 0, the value of dName must be set to Sunday.


Note that a break statement must be used at the end of each case.


without the break statement, the switch-case functions in a complex fashion.


It will be explained in subsequent part of the tutorial.

switch(day) {

case 0:

dName = “Sunday”;

break;

case 1:

dName = “Monday”;

break;

case 2:

dName = “Tuesday”;

break;

case 3:

dName = “Wednesday”;

break;

case 4:

dName = “Thursday”;

break;

case 5:

dName = “Friday”;

break;

case 6:

dName = “Saturday”;

break;

}

Similarly, let us type the remaining cases.


case 1 colon

dName equal to within double quotes Monday semicolon

break semicolon

case 2 colon

dName equal to within double quotes Tuesday semicolon

break semicolon

case 3 colon

dName equal to within double quotes Wednesday semicolon

break semicolon

case 4 colon

dName equal to within double quotes Thursday semicolon

break semicolon

case 5 colon

dName equal to within double quotes Friday semicolon

break semicolon

case 5 colon

dName equal to within double quotes Saturday semicolon

break semicolon

Then close the brackets.

Let us now add a print statement and see the code in action.
Type System.out.println(dName);


save and run.


Point to output

Type System dot out dot println within brackets dName semicolon.


Save and run.


As we can see, the output is Wednesday corresponding to the case 3.


Let us change the value of day and see the result

Change day = 3 to day = 0


save and run.


Point to output

Change 3 to 0


Save and Run


As we can see, the output is Sunday corresponding to the case 0


Now what if there is no case corresponding to the value. Let us see

Change day = 0 to day = -1

save and run. Point to output

As we can see, there is no output.


But it would be better if we could have a case for all other values.


That is done by using the default keyword.

After the last case, type this

default:

dName = “Wrong Choice”

break;


save and run.


Point to output

After the last case, type


default colon

dName equal to within double quotes Wrong Choice

break semicolon


Note that we simply use the keyword default .


We do not say case default.


Let us now run the code.


As we can see, the default case is executed and the required message is printed.


Let us try with another random value.

Change day = -1 to day = 15

save and run. Point to output

Change -1 to 15

As we can see, again the default case is executed.

Now let us see what happens if we remove the break statement.
Change day = 15 to day = 4

Remove the break in case 4 statement there

Let us change day = 15 to day = 4


And remove the corresponding break statement for day=4


Save and run

Point to output Although the case is 4, we get the output as Friday and not Thursday.
Highlight case 4 and case 5 This is because of the way switch case works.


First the value of day is compared with 0.


Then with 1 and then with 2 and so on with all the possible cases.

When a match is found, it executes all the case from the match onwards.


In our case, it executed case 5 after case 4 .

Then it stops because of the break statement in case 5.

To avoid that, we need to add a break statement in each case.
Type in case 4

break;

Let us now add the break statement we removed.


Type break semicolon.


Now let us run the code.

Save and run. Point to output As we can see, now only case 4 is executed.


As a rule, remember to use a break statement in every case to avoid errors.

Minimize the Eclipse window and switch to slides.


Slide 6

Summary

We have come to the end of this tutorial.

In this tutorial we have learnt how to use switch case construct and how to use break statement.

Slide 7Assignment Write a program that has a name and gender and a switch case statement that prints “Hello Mr....” for males and “Hello Ms...” for females.
Slide 8About the Spoken Tutorial Project
  • It summarises the Spoken Tutorial project
  • If you do not have good bandwidth, you can download and watch it


To know more about the Spoken Tutorial project, watch the video available at the following link, that summarises the project.Alternatively, you can download and watch it.
Slide 9Spoken Tutorial WorkshopsThe Spoken Tutorial Project Team
  • Conducts workshops using spoken tutorials
  • Gives certificates for those who pass an online test


The Spoken Tutorial Project Team. Conducts workshops using spoken tutorials and gives certificates for those who pass an online test. For more details, please write to contact AT spoken HYPHEN tutorial DOT org.
Slide 10Acknowledgement
  • Spoken Tutorial Project is a part of the Talk to a Teacher project
  • It is supported by the National Mission on Education through ICT, MHRD, Government of India
  • More information on this Mission is available at


Spoken Tutorial Project is a part of the Talk to a Teacher project and is supported by the National Mission on Education through ICT, MHRD, Government of India. More information on this Mission is available at spoken HYPHEN tutorial DOT org SLASH NMEICT HYPHEN Intro
Slide 11About the contributor
  • This tutorial has been contributed by TalentSprint
  • www.talentsprint.com
  • Thanks for joining


This tutorial has been contributed by TalentSprint. Thanks for joining.



Contributors and Content Editors

Arya, Sneha

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