Difference between revisions of "Java/C2/while-loop/English-timed"

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|-
 
|-
 
| 00:02
 
| 00:02
| Welcome to the spoken tutorial on''' While Loop '''in java'''.'''
+
| Welcome to the spoken tutorial on '''While Loop''' in java.
  
 
|-
 
|-
 
|  00:06
 
|  00:06
|  In this tutorial, you will learn '''About the while loop.'''
+
|  In this tutorial, you will learn: * about the '''while loop'''
 
+
* how to use it.
'''How To use it.'''
+
  
 
|-
 
|-
 
|  00:12
 
|  00:12
|  For this tutorial we are using
+
|  For this tutorial, we are using:
 
+
 
'''Ubuntu 11.10''',  
 
'''Ubuntu 11.10''',  
 
 
'''JDK 1.6''' and  
 
'''JDK 1.6''' and  
 
 
'''Eclipse 3.7'''
 
'''Eclipse 3.7'''
  
 
|-
 
|-
 
|  00:21
 
|  00:21
|  To follow this tutorial, you must have knowledge of '''relational operators in Java'''  
+
|  To follow this tutorial, you must have knowledge of '''relational operators in Java'''.
 
+
 
+
 
+
  
 
|-
 
|-
 
|  00:26  
 
|  00:26  
| If not, for relevant tutorials please visit our website as shown. [http://spoken-tutorial.org/ http][http://spoken-tutorial.org/ ://][http://spoken-tutorial.org/ spoken][http://spoken-tutorial.org/ -][http://spoken-tutorial.org/ tutorial][http://spoken-tutorial.org/ .][http://spoken-tutorial.org/ org]
+
| If not, for relevant tutorials, please visit our website as shown. [http://spoken-tutorial.org]
 
+
 
|-
 
|-
 
|  00:36
 
|  00:36
| Here is the structure of a while loop.  
+
| Here is the '''structure''' of a '''while loop'''.  
  
 
|-
 
|-
Line 47: Line 40:
 
|  00:41
 
|  00:41
 
| One is the '''loop running condition''' and the  second is the '''loop variable.'''
 
| One is the '''loop running condition''' and the  second is the '''loop variable.'''
 
  
 
|-
 
|-
 
|  00:48
 
|  00:48
|  Let us now look at an example. Switch to Eclipse
+
|  Let us now look at an example. Switch to '''Eclipse'''.
  
 
|-
 
|-
 
|  00:55
 
|  00:55
| Here We have the eclipse IDE and  the skeleton  required  for rest of the code
+
| Here, we have the '''eclipse IDE''' and  the skeleton  required  for rest of the code.
 
+
  
 
|-
 
|-
 
|  01:00
 
|  01:00
| I have created a class WhileDemo and added the main method to it.
+
| I have created a '''class WhileDemo''' and added the '''main method''' to it.
  
 
|-
 
|-
 
|  01:05
 
|  01:05
|  | We shall print numbers from 1 to 10 using a while loop. Type '''''int n = 1'' '''''
+
|  | We shall print numbers from '''1''' to '''10''' using a '''while loop'''. Type: '''int n = 1'''.
 
+
 
+
  
 
|-
 
|-
 
| 01:15
 
| 01:15
|  This variable n is going to be our loop variable
+
|  This variable 'n' is going to be our '''loop variable'''.
  
 
|-
 
|-
 
|  01:21
 
|  01:21
type '''''while ''''in ''parenthesis '''n''' less than or  equal to'' '''''10''''' open and close braces
+
Type: '''while''' in parenthesis '''n''' less than or  equal to '''10''' open and close braces.
  
 
|-
 
|-
 
|  01:33
 
|  01:33
| This condition is called   looping running condition.
+
| This condition is called '''looping running condition'''.
 
+
  
 
|-
 
|-
 
|  01:37
 
|  01:37
| It means the loop will run as long as this condition is true.
+
| It means the '''loop''' will '''run''' as long as this condition is true.
 
+
  
 
|-
 
|-
 
|  01:42
 
|  01:42
| In our case, it will run as long as the value of '''n''' is less than or equal to 10.
+
| In our case, it will run as long as the value of 'n' is less than or equal to 10.
 
+
  
 
|-
 
|-
 
|  01:47
 
|  01:47
| And it will stop only when the value of '''n''' become greater than 10.
+
| And it will stop only when the value of 'n' becomes greater than 10.
  
 
|-
 
|-
 
|  01:53
 
|  01:53
|   Inside the loop, we shall print the value of '''n'''  
+
| Inside the '''loop''', we shall print the value of 'n'.  
  
 
|-
 
|-
 
|  01:58
 
|  01:58
|   '''System.out.println(n);''' and then increment '''n = n + 1;'''
+
| '''System.out.println(n);''' and then increment '''n = n + 1;'''
 
+
 
+
 
+
  
 
|-
 
|-
 
| 02:12
 
| 02:12
| This way, first 1 is printed and then the value of n becomes 2.  
+
| This way, first 1 is printed and then the value of 'n' becomes 2.  
  
 
|-
 
|-
 
|  02:18
 
|  02:18
| Then the loop condition is checked.
+
| Then the '''loop condition''' is checked.
 
+
 
   
 
   
 
|-
 
|-
 
|  02:21
 
|  02:21
| Since it is true2 is printed and   n becomes 3.
+
| Since it is true, 2 is printed and n becomes 3.
  
 
|-
 
|-
 
|  02:25
 
|  02:25
|  And so on loop progresses untill 10 is printed  after that n becomes 11 and the condition is not true and the loop will stop
+
|  And so on.. loop progresses until 10 is printed. After that 'n' becomes 11 and the condition is not true and the '''loop''' will stop.
 
+
+
 
+
  
 
|-
 
|-
 
|  02:37
 
|  02:37
|  So Let us see the code in action.
+
|  So, let us see the code in action.
  
 
|-
 
|-
 
|  02:39
 
|  02:39
|  Save and  run.
+
'''Save''' and  '''run'''.
  
 
|-
 
|-
 
|  02:47
 
|  02:47
 
| As we can see, the numbers from 1 to 10 are printed.
 
| As we can see, the numbers from 1 to 10 are printed.
 
  
 
|-
 
|-
 
|  02:52
 
|  02:52
| Now we shall  print numbers from '''50''' to '''40'''
+
| Now we shall  print numbers from '''50''' to '''40'''.
  
 
|-
 
|-
 
|  02:58
 
|  02:58
|  So We start with 50. ''' Change n = 1 to n = 50'''
+
|  So, we start with 50.   Change '''n = 1''' to '''n = 50'''.
  
 
|-
 
|-
 
| 03:03
 
| 03:03
 
| And We go till 40.
 
| And We go till 40.
 
  
 
|-
 
|-
 
|  03:05
 
|  03:05
| In other words as long as n ''is greater than or equal to ''40. So change the condition to  n ''  greater than or equal to ''40.
+
| In other words, as long as 'n' is greater than or equal to 40. So, change the condition to  n   greater than or equal to 40.
 
+
 
+
  
 
|-
 
|-
 
| 03:16  
 
| 03:16  
| And since we are looping from a bigger number to a smaller number, we have decrement the loop variable.
+
| And since we are looping from a bigger number to a smaller number, we have decremented the loop variable.
 
+
  
 
|-
 
|-
 
|  03:22
 
|  03:22
| So Change '''n=n + 1''' to '''n=n - 1'''
+
| So Change '''n=n+1''' to '''n=n-1'''.
 
+
 
+
 
   
 
   
 
|-
 
|-
 
| 03:27
 
| 03:27
| Save and run. As we can see, the  the numbers 50 to 40 have been printed
+
| '''Save''' and '''run'''. As we can see, the numbers 50 to 40 have been printed.
  
 
|-
 
|-
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|-
 
|-
 
|  03:48
 
|  03:48
|  To do that, we start with 7  
+
|  To do that, we start with 7.
 
+
  
 
|-
 
|-
 
|  03:50
 
|  03:50
| So change '''n = 50''' to '''n = 7'''and then end with 70.
+
| So, change '''n = 50''' to '''n = 7''' and then end with 70.
 
+
  
 
|-
 
|-
 
|  03:57
 
|  03:57
| Change the condition to n''' ''less than equal to '''''70'''
+
| Change the condition to '''n''' less than equal to '''70'''.
 
+
  
 
|-
 
|-
 
|  04:03
 
|  04:03
| This way, we make sure the loop stops at 70.
+
| This way, we make sure the '''loop''' stops at 70.
  
 
|-
 
|-
 
|  04:07
 
|  04:07
| To get the multiples, we shall increment the loop variable by 7.
+
| To get the multiples, we shall increment the '''loop variable''' by 7.
 
+
  
 
|-
 
|-
 
|  04:12
 
|  04:12
| So, change ''' n=n - 1''' to '''n=n + 7'''
+
|So, change '''n=n-1''' to '''n= n+7'''.
 
+
  
 
|-
 
|-
 
|  04:18
 
|  04:18
|  This way first 7 is printed and  then n becomes 14, 14 is printed and so on untill 70. Save and run
+
|  This way, first 7 is printed and  then 'n' becomes 14, 14 is printed and so on until 70. '''Save''' and '''run'''.
  
 
|-
 
|-
 
|  04:33
 
|  04:33
|  | As we can see, the first 10 multiples of 7 are  printed.
+
|  | As we can see, the first 10 multiples of 7 are  printed.
 
+
  
 
|-
 
|-
 
|  04:43
 
|  04:43
| We can also use a while loop to get the sum of digits of a number.
+
| We can also use a '''while loop''' to get the sum of digits of a number.
 
+
  
 
|-
 
|-
Line 226: Line 191:
 
|-
 
|-
 
|  04:49
 
|  04:49
| First clear the main method.
+
| First, clear the '''main method'''.
  
 
+
|-
|-
+
 
|  04:54
 
|  04:54
| int '''n''' ''equal to'' '''13876'''. This is the number
+
| '''int n''' equal to '''13876'''. This is the number.
  
 
|-
 
|-
 
| 05:02
 
| 05:02
| Then '''int dSum '''''equal to'' '''0'''The variable dsum with symbolic for digit sum will contain the sum of digits
+
| Then '''int dSum''' equal to '''0''' The variable '''dsum''' with symbolic for digit sum will contain the sum of digits.
 
+
+
  
 
|-
 
|-
 
|  05:18
 
|  05:18
|  Type while, n greater than 0 open close parenthesis
+
|  Type: '''while n''' greater than '''0''' open close parenthesis.
 
+
  
 
|-
 
|-
Line 253: Line 214:
 
|-
 
|-
 
|  05:36
 
|  05:36
| To do that we use modulo operator.  
+
| To do that, we use '''modulo operator'''.  
 
+
+
 
+
  
 
|-
 
|-
 
|  05:40
 
|  05:40
| Type '''dSum = dSum + (n % 10)''' So we get the unit digit and add it to dsum
+
| Type: '''dSum = dSum + (n % 10)''' So, we get the unit digit and add it to '''dsum'''.
  
 
|-
 
|-
 
|  05:52
 
|  05:52
|After that  we remove the digit by dividing   by 10.   n = n / 10
+
|After that  we remove the digit by dividing by 10. n = n / 10
  
 
|-
 
|-
 
| 06:08
 
| 06:08
| So when the   loop is  run  for the first time, '''dSum '''will be 6 and n will be 1387.
+
| So when the '''loop''' is  '''run''' for the first time, '''dSum''' will be 6 and 'n' will be 1387.
  
 
|-
 
|-
 
| 06:15
 
| 06:15
| And when the loop is run for the the second time, '''dSum''' will be sum of 7 and 6 which is 13and '''n''' will become 138.
+
| And when the loop is '''run''' for the second time, '''dSum''' will be sum of 7 and 6 which is 13 and 'n' will become 138.
 
+
  
 
|-
 
|-
 
|  06:22
 
|  06:22
| So on, as the loop progresses, the digits will be  removed from '''n''' and finally
+
| So on as the loop progresses, the digits will be  removed from '''n''' and finally
  
 
|-
 
|-
 
|  06:28
 
|  06:28
|   '''n'''   become zero.After that the condition n greater than 0 will be false and the loop will stop
+
| '''n''' becomes zero. After that the condition 'n greater than 0' will be false and the loop will stop.
  
 
|-
 
|-
 
| 06:36
 
| 06:36
|   So let us now add a print statement
+
| So, let us now add a print statement:
 
|-
 
|-
 
|  06:42
 
|  06:42
|   '''System.out.println(dSum)'''
+
| '''System.out.println(dSum)'''
  
 
|-
 
|-
 
|  06:51
 
|  06:51
| Let us see the code and action. Save and run
+
| Let us see the code and action. '''Save''' and '''run'''.
 
|-
 
|-
 
|  06:59
 
|  06:59
| As we can see the sum of digit which is 25 has been printed
+
| As we can see, the sum of digit which is 25 has been printed.
 
   
 
   
 
|-
 
|-
 
| 07:06  
 
| 07:06  
| This way, a while loop, which is one of the most fundamental constructs in programming, can be used.
+
| This way, a '''while loop''' which is one of the most fundamental '''constructs''' in programming, can be used.
  
 
|-  
 
|-  
 
|  07:16
 
|  07:16
|  This brings us to the end of the tutorial.  
+
|  This brings us to the end of the tutorial.  
 
+
  
 
|-
 
|-
 
|  07:20
 
|  07:20
| In this tutorial we have learnt
+
| In this tutorial, we have learnt:
 
+
 
* About while loop
 
* About while loop
* how to use it
+
* How to use it.
 
+
 
+
  
 
|-
 
|-
 
|07:26
 
|07:26
| As an assignment for this tutorial solve the following problem.
+
| As an assignment for this tutorial, solve the following problem.
 
+
  
 
|-
 
|-
Line 326: Line 278:
 
|-
 
|-
 
|07:37
 
|07:37
|To know more about the '''Spoken Tutorial''' project, watch the video available at the following link, that summarizes the Spoken Tutorial project
+
|To know more about the Spoken Tutorial project, watch the video available at the following link, that summarizes the Spoken Tutorial project.
  
 
|-
 
|-
Line 334: Line 286:
 
|-
 
|-
 
| 07:50  
 
| 07:50  
|  The 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. Gives certificates for those who pass an online test.
  
 
|-
 
|-
Line 342: Line 294:
 
|-
 
|-
 
| 08:03
 
| 08:03
| '''Spoken Tutorial '''Project is a part of the '''Talk to a Teacher''' project.
+
| Spoken Tutorial Project is a part of the Talk to a Teacher project.
 +
 
 
|-
 
|-
 
|  08:07
 
|  08:07
|  It is supported by the '''National Mission on Education through ICT, MHRD, Government of India.
+
|  It is supported by the National Mission on Education through ICT, MHRD, Government of India.
 +
 
 
|-
 
|-
 
|  08:12
 
|  08:12
| '''More information on this Mission is available at the following link
+
| More information on this mission is available at the following link.
  
 
|-
 
|-
 
|  08:17
 
|  08:17
 
|  This tutorial has been contributed by '''TalentSprint'''. Thanks for joining.
 
|  This tutorial has been contributed by '''TalentSprint'''. Thanks for joining.
 
 
 
  
 
|}
 
|}

Revision as of 23:17, 25 March 2015

Time Narration
00:02 Welcome to the spoken tutorial on While Loop in java.
00:06 In this tutorial, you will learn: * about the while loop
  • how to use it.
00:12 For this tutorial, we are using:

Ubuntu 11.10, JDK 1.6 and Eclipse 3.7

00:21 To follow this tutorial, you must have knowledge of relational operators in Java.
00:26 If not, for relevant tutorials, please visit our website as shown. [1]
00:36 Here is the structure of a while loop.
00:39 It has two parts.
00:41 One is the loop running condition and the second is the loop variable.
00:48 Let us now look at an example. Switch to Eclipse.
00:55 Here, we have the eclipse IDE and the skeleton required for rest of the code.
01:00 I have created a class WhileDemo and added the main method to it.
01:05 We shall print numbers from 1 to 10 using a while loop. Type: int n = 1.
01:15 This variable 'n' is going to be our loop variable.
01:21 Type: while in parenthesis n less than or equal to 10 open and close braces.
01:33 This condition is called looping running condition.
01:37 It means the loop will run as long as this condition is true.
01:42 In our case, it will run as long as the value of 'n' is less than or equal to 10.
01:47 And it will stop only when the value of 'n' becomes greater than 10.
01:53 Inside the loop, we shall print the value of 'n'.
01:58 System.out.println(n); and then increment n = n + 1;
02:12 This way, first 1 is printed and then the value of 'n' becomes 2.
02:18 Then the loop condition is checked.
02:21 Since it is true, 2 is printed and n becomes 3.
02:25 And so on.. loop progresses until 10 is printed. After that 'n' becomes 11 and the condition is not true and the loop will stop.
02:37 So, let us see the code in action.
02:39 Save and run.
02:47 As we can see, the numbers from 1 to 10 are printed.
02:52 Now we shall print numbers from 50 to 40.
02:58 So, we start with 50. Change n = 1 to n = 50.
03:03 And We go till 40.
03:05 In other words, as long as 'n' is greater than or equal to 40. So, change the condition to n greater than or equal to 40.
03:16 And since we are looping from a bigger number to a smaller number, we have decremented the loop variable.
03:22 So Change n=n+1 to n=n-1.
03:27 Save and run. As we can see, the numbers 50 to 40 have been printed.
03:42 Now we shall print the first 10 multiples of 7.
03:48 To do that, we start with 7.
03:50 So, change n = 50 to n = 7 and then end with 70.
03:57 Change the condition to n less than equal to 70.
04:03 This way, we make sure the loop stops at 70.
04:07 To get the multiples, we shall increment the loop variable by 7.
04:12 So, change n=n-1 to n= n+7.
04:18 This way, first 7 is printed and then 'n' becomes 14, 14 is printed and so on until 70. Save and run.
04:33 As we can see, the first 10 multiples of 7 are printed.
04:43 We can also use a while loop to get the sum of digits of a number.
04:47 Let us see how to do so.
04:49 First, clear the main method.
04:54 int n equal to 13876. This is the number.
05:02 Then int dSum equal to 0 The variable dsum with symbolic for digit sum will contain the sum of digits.
05:18 Type: while n greater than 0 open close parenthesis.
05:27 The reason for using this condition will be evident in a while.
05:32 To get the sum of digits, we must first get the digits.
05:36 To do that, we use modulo operator.
05:40 Type: dSum = dSum + (n % 10) So, we get the unit digit and add it to dsum.
05:52 After that we remove the digit by dividing by 10. n = n / 10
06:08 So when the loop is run for the first time, dSum will be 6 and 'n' will be 1387.
06:15 And when the loop is run for the second time, dSum will be sum of 7 and 6 which is 13 and 'n' will become 138.
06:22 So on as the loop progresses, the digits will be removed from n and finally
06:28 n becomes zero. After that the condition 'n greater than 0' will be false and the loop will stop.
06:36 So, let us now add a print statement:
06:42 System.out.println(dSum)
06:51 Let us see the code and action. Save and run.
06:59 As we can see, the sum of digit which is 25 has been printed.
07:06 This way, a while loop which is one of the most fundamental constructs in programming, can be used.
07:16 This brings us to the end of the tutorial.
07:20 In this tutorial, we have learnt:
  • About while loop
  • How to use it.
07:26 As an assignment for this tutorial, solve the following problem.
07:29 Given a number, compute its reverse by using a while loop. Example: 19435 => 53491
07:37 To know more about the Spoken Tutorial project, watch the video available at the following link, that summarizes the Spoken Tutorial project.
07:45 If you do not have good bandwidth, you can download and watch it.
07:50 The Spoken Tutorial Project Team: Conducts workshops using spoken tutorials. Gives certificates for those who pass an online test.
07:57 For more details, please write to contact AT spoken HYPHEN tutorial DOT org.
08:03 Spoken Tutorial Project is a part of the Talk to a Teacher project.
08:07 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
08:12 More information on this mission is available at the following link.
08:17 This tutorial has been contributed by TalentSprint. Thanks for joining.

Contributors and Content Editors

Gaurav, PoojaMoolya, Pratik kamble, Sandhya.np14, Sneha