PHP-and-MySQL/C2/Loops-While-Statement/English-timed

Time	Narration
00:00	Hello and welcome. I have decided to create separate tutorials for each looping statement.
00:07	I want to keep it simple. This will be useful as a reference also if you need to refer to how a particular loop works.
00:17	In this tutorial, we will learn about the while loop.
00:21	A while loop checks for a condition at the start of the loop and executes the code depending on whether this condition is True or not.
00:38	For example, I'll start my while loop here and this is my condition and this is my block.
00:51	I'll represent my block between curly brackets.
00:56	My condition is here. Now, in the if statement, for example I used 1==1.
01:04	Now, if I say 'test' or 'loop' here,
01:07	this is Loop here and then a break . Now what happens is as long as 1=1, it would create a loop.
01:17	If I do something here, let's try this.
01:22	It would probably crash your browser because the loop would be repeated as long as 1=1 and for infinite number of times, 1 will always equal to 1.
01:34	So, since the loop will always be repeated, your browser will crash.
01:40	Let's say while a variable '$num' is smaller or equal to 10 and under echo I can say: $num ++.
01:57	'++' is an arithmetical operator. What it basically does is, it increases 'num' by 1. It is the same as writing 'num =num +1'.
02:16	So, it takes 'num' and says that it is equal to the value of 'num plus 1'.
02:23	So, this again is an arithmetical operator. What's going to happen is -
02:29	we are going to say 'num' less than or equal to (<=) 10; if 'yes' then echo Loop and then say add 1 on to the variable 'num'.
02:41	But, what we should really do is create '$num = 1' at the moment. So Loop once at 1. This will then equals to 2, then 3, then 4, then all the way up to 10 and then this will stop.
03:01	After that, the rest of the code, below this, will continue.
03:06	So, we said this 1 and see what we will we get. Okay, we got Loop 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 times.
03:20	Now to make it more fun, I'll say Loop 1 and I'll concatenate 'num' to the end of that.
03:27	In fact, let's make it simpler and say '$num' inside - it will make it much easier to read.
03:37	Okay. I'll say loop 1 and add 1 and then I'll say loop 2 and I'll add another 1; and that's loop 3 and I'll add another 1 up to 10.
03:49	Let's open this up. Refresh it. There you go. You got loop 1,2,3 all the way up to 10 as you can see.
03:58	Let's change this value here to 100. Refresh that. You can see it has gone to hundred. The bigger the number, the longer it will take to loop.
04:08	Let's take 6000. Let's refresh that. It's going to take a while. There you go - up to 6000. So it's very efficient in this way.
04:20	You can try combining this with an array to create a program that echoes out the alphabets inside the array.
04:27	You can use loop to echo out every single value of an array.
04:32	Just give it a go. I will probably do this in one of my tutorial - not in the basics section though.
04:40	However, this is the basic structure. What I also recommend you to do is, create a variable here called '$max' and put your maximum value here.
04:53	This will do exactly the same thing. It's just a lot more easy to read and you can declare all this here and this would be a reference to it.
05:03	If you have more than 1 loop, I prefer it for readability and flexibility for my program. Okay. So, that's a while loop. Let me summarize. It checks the condition of the start.
05:17	If the condition is True, it would execute this block of code and you can do things like 'echo alpha'.
05:24	Your variable is being incremented. Make sure that you do increment your variable, otherwise it will loop for infinity.
05:32	Thanks for watching. This is Sidharth for the Spoken Tutorial Project, signing off. Goodbye.

Contributors and Content Editors

Minal, PoojaMoolya, Pratik kamble, Sandhya.np14