Java/C2/while-loop/English

Title of script: While Loop

Author: TalentSprint

Keywords: loop, conditions, while loop, video tutorial

Visual Cue	Description
Slide 1 Welcome	Welcome to the spoken tutorial on While Loop in java.
Slide 2 Learning Outcomes	In this tutorial, you will learn About the while loop. To use it.
Slide 3 Tools Used	For this tutorial we are using Ubuntu 11.10, JDK 1.6 and Eclipse 3.7
Slide 4 Prerequisites	To follow this tutorial, you must have knowledge on relational operators in Java If not, for relevant tutorials please visit our website which is as shown. http://spoken-tutorial.org
Slide 5 While loop	Here is the structure of a while loop. It has two parts. One is the loop running condition and the other is the loop variable. Let us look at an example. Switch to Eclipse
Point to the code Minimize Slides and open Eclipse Eclipse should contain the following code. public class WhileDemo{ public static void main(String[] args){ } }	We have the skeleton code required. I have created a class WhileDemo and added the main method to it.
Type in main method, int n = 1;	We shall print numbers from 1 to 10 using a while loop. Type int n = 1 semi-colon.
Highlight int n = 1;	We have created an integer n that we would be using inside the loop. This is called the loop variable.
Type in next line, while (n <= 10)	Then type while within parenthesis n less than equalto 10
Highlight while (n <= 10)	This statement is called the looping condition. It means the loop will run as long as this condition is true. In our case, it will run as long as the value of n is less than or equal to 10. And it will stop only when the value of n become greater than 10.
Change the while... to while (n <= 10) { System.out.println(n); n = n + 1; }	Inside the loop, we shall print the value of n and then increment it. Type System.out.println(n); n = n + 1;
Highlight print statement Then increment statement	This way, first 1 is printed and then the value of n becomes 2.
Highlight condition Highlight print statement Then increment statement.	Then the loop condition is checked. The condition is true. Then 2 is printed and the value of n becomes 3.
Highlight condition	This happens till 10 is printed and the value of n becomes 11. Once the value of n is 11, the condition n <= 10 is not true. And hence the loop stops. Let us see the code in action.
Save and run. Point to output	Save. Run the code. As we can see, the numbers from 1 to 10 are printed. Now let us print numbers from 50 to 40
Change n = 1 to n = 50	We start with 50. So Change n = 1 to n = 50
Change n <= 10 to n >= 40	We go till 40. In other words as long as n is greater than or equal to 40. Change n lessthan equal to 10 to n greater than equal to 40
Change n = n + 1 to n = n - 1	since we are looping from a bigger number to a smaller number, we have decrement the loop variable. Change n + 1 to n - 1 Let us now see the output.
Save and run. Point to output	As we can see, the output is as expected. Now we shall print the first 10 multiples of 7.
Change n = 50 to n = 7 Change n >= 40 to n <= 70 Change n = n – 1 to n = n + 7	To do that, we start with 7 and end with 70. So change n = 50 to n = 7 n greater than equal to 40 to n less than equal to 70 This way, we make sure the loop stops at 70.
	To get the multiples, we shall increment the loop variable by 7. So, change n - 1 to n + 7 Save. Run.
Save and run. Point to output	As we can see, the output is the first 10 multiples of 7. We can also use a while loop to get the sum of digits of a number. Let us see how to do so.
Change n = 7 to n = 13876	First clear the main method. We start with the number. n equal to 13876
Add int dSum = 0 as the next line	int dSum equal to 0 This variable will contain the sum of digits.
Change n <= 70 to n > 0	Change n less than equal to 70 to n greater than 0 The reason for using this condition will be evident in a while.
Remove n = n + 7 and add this dSum = dSum + (n % 10); n = n / 10;	To get the sum of digits, we must first get the digits. We do that by using the modulo operator. Type dSum = dSum + (n % 10)
	Now after adding that digit, we remove the digit by dividing the number by 10. Type n = n / 10
Point to the code : dSum	So when the loop runs for the first time, dSum will be 6 and n will be 1387.
Point to the code : dSum and n	After the second run, dSum will be 13, which is the sum of last two digits n will become 138. So on, as the loop progresses, the digits will be added to dSum. And the value of n will become zero.
	Finally, we print the dSum.
Change println(n) to println(dSum) save and run. Point to output	Type System.out.println(dSum) Save and run. As we can see, the sum of digits has been printed.
	This way, a while loop, is one of the most fundamental constructs in programming, can be used.
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 The while loop how to use it
Slide 7Assignment	As an assignment for this tutorial solve the following problem. Given a number, compute its reverse by using a while loop. Example: 19435 => 53491
Slide 8About the Spoken Tutorial Project Watch the video available at[1]http://spoken-tutorial.org/What_is_a_Spoken_Tutorial It summarizes 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 summarizes the Spoken Tutorial project If you do not have good bandwidth, 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 For more details, please write to contact@spoken-tutorial.org	The Spoken Tutorial Project Team, Conducts workshops using spoken tutorials, 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 http://spoken-tutorial.org/NMEICT-Intro	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 the following link
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

Chandrika, Sneha