[RESOLVED] day three of learning php: my story & help with simple problem

whiskerbiskit

hey guys!
i'm an old fart trying to learn programming. i shoulda done this back in the 80's when i started out playing on a commodore 64. by now i'd be a hell of a programmer if i had put my mind to it. now i need to fix a site written in php and mysql that is costing me a fortune from rentacoder. so i picked up a book called sams teach yourself php, mysql & apache.

on days one and two i learned through the 6th chapter which teaches up to the various ways of doing loops. at a conceptual level i've mastered this much but putting theory to practice has been tough.

take, for example, this very simple code i came up with:

<?php
$var=rand(1,5);
while ($var==5)
{
echo $var;
}
?>

what i intended in this exercise was for the code to echo random numbers to the screen until it hit 5. instead, the screen stays blank on every refresh. the statement is false every time so it never echoes anything.

dagon

this will achive what you are after (not many practical uses i can think of)

 <?php
	while(1){
		$var= rand(1,5);
		echo $var;
		if($var == 5){
			break;
		}
	}
	?>

if you want it to break on 5 but not echo 5, move the echo statement below the if clause

whiskerbiskit

thanks - you're right that it's pretty much useless. however, what i was after was an explanation of why it didn't work. if the contents of $var are random on each iteration then why does it not echo the current value?

i know this is very newbie... like i said, i'm only a day three! :-)

Kudose

Hello.

The problem with your code is that it only does one iteration.

<?php
  $var=rand(1,5); // get a number
  while ($var==5) { // while the number is 5, print the number
    echo $var;
  }
?>

So, if $var gets the number 5 (1 in 5 chance) then your script will continue to print 5 forever (since you do not change the value in the loop).

I think you are looking for

do {
  $num = rand(1,5);
  echo $num;
  if($num == 5)
    exit;
} while($num != 5);

Alternatively (there are a million ways to do this)

<?php
  $num = 0;
  while($num != 5){
    $num = rand(1,5);
    echo $num;
  }

whiskerbiskit

thank you kudose!
i had a vague idea that was the problem but you spelled it out for me! on to other problems.

thanks again

Kudose

Your welcome. Can you please mark this thread resolved if you have no more questions?