Java/C2/do-while/Gujarati
From Script | Spoken-Tutorial
Time' | Narration |
00:01 | Welcome to the spoken tutorial on do-while Loop in java. |
00:06 | In this tutorial, you will learn about
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00:12 | For this tutorial we are using
Ubuntu 11.10, JDK 1.6 and Eclipse 3.7 |
00:20 | To follow this tutorial, you musthave knowledge of while loop in java.
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00:25 | If not, for relevant tutorials please visit our website as shown.
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00:32 | Here is the structure for do-while loop.
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00:37 | Notice that it is similar to a while loop.
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00:40 | It has two parts.
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00:42 | First is the loop running condition. And the second is the loop variable |
00:51 | The only difference is that the condition is written after the do block.
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00:58 | And so the condition is checked after the execution of the statements inside the do block
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01:05 | Now let us see an example. |
01:07 | Switch to eclipse |
01:11 | Here we have Eclipse IDE and the skeleton required for the rest of the code.
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01:17 | We have created a class DoWhileDemo and added the main method to it.
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01:22 | We are going to print the numbers from 1 to 10 using a do-while loop.
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01:27 | Type
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01:29 | int n equalto 1
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01:32 | n is going to be loop variable. |
01:36 | then type do |
01:40 | open and close braces |
01:44 | Inside the bracesSystem.out.println(n); |
01:55 | We shall print the value of n and then increment it. n equalto n plus 1; |
02:05 | And we do this as long as
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02:08 | n is less than or equal to 10
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02:10 | Outside the braces Type while in paranthesis(n less than equalto 10) |
02:20 | And close the do-while using a semi-colon |
02:25 | Let us see the code in action.
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02:28 | Save and Run. |
02:37 | We see that, the numbers from 1 to 10 are printed. |
02:42 | now Let us understand how the code is executed. |
02:47 | First, the value 1 is printed and then n becomes 2.
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02:52 | And then, the condition is checked.
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02:55 | since it is true, again 2 is printed and n becomes 3.
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03:00 | And so on till all the 10 numbers are printed and the value of n becomes 11.
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03:06 | When n = 11, the condition fails and the loop stops.
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03:11 | Now Let us print numbers from 50 to 40 in decreasing order. |
03:17 | So we start with 50. |
03:19 | Change n = 1 to n = 50. |
03:23 | Since we are looping from a bigger number to a smaller number, we decrement the loop variable.
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03:29 | So Change n = n + 1 to n = n - 1 |
03:34 | We loop as long as n is greater than or equal to 40.
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03:40 | So Change the condition to n >= 40 |
03:48 | Let us look at the output. |
03:50 | Save and Run. |
03:57 | As we can see, the numbers from 50 to 40 are printed. |
04:02 | Now let us try a different logic using the do-while loop. |
04:10 | Given a number, we shall find out if it is a perfect square or not. |
04:15 | First Clear the main method. |
04:19 | ThenType int n = 25; |
04:25 | We shall see if the value in n is a perfect square or not. |
04:32 | Then typeint x = 0;
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04:37 | We shall use x to store the square root of the number if it is a perfect square. |
04:44 | Then Type do
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04:46 | Open and close braces. |
04:49 | Inside the bracesx equal to x plus 1 |
04:55 | And outside the braces
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04:58 | while in paranthesis (x into x < n)
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05:06 | And Close the do-while usinga semi-colon |
05:10 | As long a x into x is less than n, we keep incrementing the value of x. |
05:16 | So when the loop stops, the reverse of this condition will be true. |
05:22 | Which means either x into x must be equal to n.
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05:26 | Or it must be greater than n. |
05:28 | If x into x is equal to n, the number is a perfect square.
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05:32 | If it is not equal to n, the number is not a perfect square. |
05:37 | So finally, we print the condition. |
05:47 | System.out.println(x * x == n); |
05:55 | Let us see the code in action. |
05:59 | Save and Run. As we can see, the output is true
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06:07 | Let us try with other perfect square. |
06:10 | Change n = 25 to n = 49 |
06:15 | Save and Run |
06:20 | We see that we get the true again . |
06:23 | Let us try with a number which is not a perfect square. |
06:26 | Change 49 to 23. Save and Run and
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06:34 | We get a false as expected.
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06:37 | Now let us see what happens when the value of n is 0. |
06:42 | Change n = 23 to n = 0 Since 0 is not a natural number, we must get a false.
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06:52 | Let us run the code. |
06:54 | Save and Run. |
07:00 | We see that we get false as expected. |
07:05 | This happens because even before the condition |
07:08 | x into x is less than n is checked, the value of x is incremented and it becomes 1
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07:16 | The loop condition fails and loop does not run. |
07:20 | This way, by using a do-while loop, we make sure that 0 is not considered as a perfect square. |
07:26 | This way, a do-while loop is used for solving a range of problems. |
07:31 | Specially, when the loop must run at least once. |
07:37 | This brings us to the end of the tutorial.
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07:40 | In this tutorial, we learnt about the |
07:42 | The do-while loop and how to use it |
07:46 | As an assignment for this tutorial, solve the following problem.
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07:50 | Given a binary number, find out its decimal equivalent. Example: 11010 => 26 |
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08:36 | This tutorial has been contributed by TalentSprint. Thanks for joining.
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