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I have just started learning coding and PHP so I have been looking at practising what I have learnt so far however am unsure how efficient or inefficient my coding is. I would appreciate your comments on the loop below. It is a simple loop and have commented out a simpler example of it. I would appreciate any advise on how I can better my coding.

//Initialize page
    $startpage = isset($_POST['page']) ? $_POST['page'] : 1;
    $endpage = 11;

    //Loop through the start and end of the page
    while($startpage < $endpage) {

        if(isset($_POST['submit'])) {
            $startpage=$startpage+1;
        }

        if($startpage < $endpage) {
            break;
        }
    }

    //Alternative option
    // if(isset($_POST['submit'])) {

        // if($startpage < $endpage) {
            // $startpage = $startpage + 1;
        // }    
    // }

EDIT

The reason I am performing a $_POST check is because I only want have the user move from one page to the next after the hit submit.

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3 Answers 3

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With what you have coded, no, it's terribly inefficient ;p. you can technically replace your code with

if(isset($_POST['submit']) && $startpage < $endpage){
    $startpage = $endpage;
}

since your logic isn't actually doing anything but increasing $startpage until it is equal to $endpage. As a tidbit, to increment by one you can do $startpage++;

Your comment //Loop through the start and end of the page also... should not be there because it doesn't make any sense, it's definitely better off to not have a comment if your comment doesn't really make sense of what's going on IMO. It kind of explains what you're trying to do, but I'm still confused :P.

Like everyone else is also saying, you seem to not really understand how a while loop works, but if you can assert otherwise I take it back :).

Here's my explanation of a while loop.

A while loop repeats itself as often as the condition you put next to it is true. So, if you say while($number is less than 11) and then increase $number by one everytime, you don't need to break; from the loop when $number is less than 11 manually, since that's what loops automatically do.

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5 Comments

Thanks for the code suggestion and I agree the example you have given certainly seems cleaner. Maybe I did not come clear across the example I am working on. I'll try again. You start on page one and you can only proceed to page 2 after submitting the form hence the $_POST['submit']. Now let's say you are page 1 and you hit submit, it executes the code if(isset($_POST['submit'])) { $startpage=$startpage+1; It increments by 1 and the proceeds to execute the next piece of code i.e. if($startpage < $endpage) { break; }
Continued from above Now seeing that the loop can only increment if there is a post the while loop will keep looping forever. The break is in the page because I want to exit to the next page i.e. 2 and not keep looping until 11 since the next increment must be user driven i.e. $_POST. If you comment out the code if($startpage < $endpage) { break; } You'll see that it'll loop forever after you submit the form. Hopefully I was clearer.
Ah hah, which means that you're using a while loop when you should actually should just being an if statement. if(isset(post) && $startpage < $endpage) $startpage++; is actually all you need. You don't seem to really have anything that needs to loop, so you've constructed something that starts a loop, and then terminates as soon as it executes. You've contrived an if statement out of a loop structure ;).
@PeanutsMonkey I think you're using a while because you're "forseeing" this having to continue to get larger, when in actuality the number only needs to be increased one time per page visit.
I would agree that I have contrived an if statement out a loop. You'll notice a simpler version of my code below which has been commented out although not as elegant as you suggestion i.e. if(isset(post) && $startpage < $endpage) $startpage++;. Will keep that in mind. Apart from practice, I have yet to learn when to use the appropriate statements. I'm attempting to adopt the mantra keep it simple however often see multiple if statements as being inefficient. Thanks for your suggestions and advise.
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I'm not entirely sure what you're trying to do, but it looks like a for loop would be more readable.

$startpage = isset($_POST['page']) ? $_POST['page'] : 1;
$endpage = 11;
for($i=$startpage; $i<$endpage; $i++)
  {
  // do something
  }

Perhaps it's personal preference, but while is more useful when you want to loop through an array of results, or when you want to keep checking the result of another function before doing something else.

Comments on your code specifically:

  1. You can rewrite $startpage=$startpage+1; as $startpage++;
  2. isset($_POST['submit']) will give you the same answer on every run through the loop, so set the result as a variable before you run the loop.
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2 Comments

Thanks. The only reason I am writing out the entire code i.e. $startpage=$startpage+1 is for my own understanding before I start writing code in shorthand. I did not realise that while is more useful when looping through an array. Is there any information that recommend which loops to use?
Which loops work best is a combination of personal preference and experience. However, I'd strongly advise reading something like Code Complete for tips like that.
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I'm not sure what you're trying to do here. That loop will run only once because of the if statement. If you're trying to print the page numbers from $startpage to $endpage, you can simple do this:

$startpage = isset($_POST['page']) ? $_POST['page'] : 1;
$endpage = 11;

while($startpage < $endpage) {
    $startpage=$startpage + 1;
}

Actually, why are you checking $_POST['submit'] here ?

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1 Comment

Sorry, I should update my original post as I should have mentioned that I am attempting to move from one page to the next one at a time which only occurs once the person submits the form. I don't agree on it just running once unless I have not understood loopong correctly seeing tha the count $startpage=$startpage + 1; only occurs when a post has occurred and since the post value occurs once and will always be less than 11, it'll loop forever. Again, I am new to PHP and may have missed something. Happy to learn something new.

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