Difference between revisions of "PHP-and-MySQL/C2/Loops-While-Statement/English-timed"

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!Narration

|0:00

|Hello and welcome. I have decided to create seperate tutorials for each looping statement.

|0:07

|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.

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|In this tutorial, we will learn about the WHILE loop

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|A WHILE loop checks for a condition at the start at the loop and executes the code depending on whether this condition is True or not

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|for example I'll start my 'WHILE loop' here and this is the condition and this is my block.

|0:51

|I'll represent my block between curly brackets.

|0:56

|My condition is here.  Now, in the 'IF statement', for example I used 1==1.

|1:04

|Now if I say 'test' or 'loop' here.

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|This is a loop here and then a break.  Now what happens is as long as 1=1, it would create a loop  

|1:17

|If I do something here, lets try this.  

|1:22

|It would probably crash your browser because the loop would be repeated as long as 1=1 and for infinite no. of times, 1 will always equal 1.

|1:34

|So since the loop will always be repeated, your browser will crash.

|1:40

|Lets say while a variable, 'num' is smaller or equal to 10 and under echo i can say - 'num ++'

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| '++' is an arithmetical operator. And what it basically does is, it increases num by 1.  It is the same as writing 'num =num +1'

|2:16

|So it takes num and says that it is equal to the value of num plus 1.

|2:23

|So this again is an arithmetical operator. What's going to happen is -  

|2:29

|We are going to say 'num' lesser than or equal to '10', if yes then echo loop and then say add 1 on to the variable num

|2:41

|But what we should really do is create 'num = 1' at the moment.  So loop once at 1.  This will then equal 2 then 3 then 4 all the way up to 10 and then it will stop

|3:01

|After that the rest of the code below this will continue.

|3:06

|So we said this 1 and see what will we get. Okay we got a loop 1,2,3,4,5,6,7,8,9,10 times

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|Now to make it more fun I'll say loop 1 and I'll concatenate 'num' to the end of that

|3:27

|In fact let's make it simpler and say 'num' inside - it will make it much easier to read

|3:37

|Okay I'll say loop 1 and add 1 and then I'll say loop 2 and I'll add another 1; that's loop 3 add another 1 up to 10.

|3:49

|Lets open this up.  Refresh it.  There you go.  You got loop 1,2,3 all the way up to 10 as you can see

|3:58

|Lets 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

|4:08

|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

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|You can try combining this with an 'array' to create a program that echoes out of the alphabet inside the 'array'

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|You can use loops to echo out every single value of an array

|4:32

|Just give it a go. I will probably do this in one my tutorial - not in the basics section though

|4:40

|However, this is the basics structure. What I also recommend you to do is create a variable here called 'max' and put your maximum value here

|4:53

|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

|5:03

|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 summarise. It checks the condition of the start

|5:17

|If the condition is True. it would execute this block of code and you can do things like 'echo alpha'

|5:24

|Your variable is being incremented. Make sure that you do increment your variable otherwise it will loop for infinity.

|5:32