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

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

|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.

|In this tutorial, we will learn about the '''while''' loop.

|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.

|For example, I'll start my '''while''' loop here and this is the '''condition''' and this is my '''block'''.

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

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

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

|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 to 1.

|Let's say '''while''' a variable 'num' is smaller or equal to 10 and under '''echo''' I can say - '''num ++'''.

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

|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'.

|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 all the way up to 10 and then it will stop.

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

|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.

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

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

|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.

|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.

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

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

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

|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.

|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

|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.

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

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