[PHP]What do you think of my function?

[timmeh39]

Well this is a script you can use at register etc.

what this does exactly:
If you have a register and the username is max 20 chars long and min 4 chars long you typ it like this:
var_between($username, int1,int1);

If it is true(between your filled integers) it wil result in a 1 else in a 0

  //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!\\
 //!!!!!!!!!!Written by TimmehXXL!!!!!!!!!!!!\\
//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!\\
function var_between($p_string, $p_num1, $p_num2){
    if(empty($p_string) || empty($p_num1) || empty($p_num2)){
        echo"PARSE ERROR: You have to fill in every parameter!";
    } elseif(!is_numeric($p_num1) || !is_numeric($p_num2)){
        echo"PARSE ERROR: The second and last parameter should be numeric!";
    } elseif($p_num1 == $p_num2){
        echo"PARSE ERROR: The last two parameters cant be the same!";
    } elseif($p_num1 > $p_num2){
        if(strlen($p_string) < $p_num2 || strlen($p_string) > $p_num1){
            return 0;
        } else {
            return 1;
        }
    } elseif($p_num2 > $p_num1) {
        if(strlen($p_string) < $p_num1 || strlen($p_string) > $p_num2 ) {
            return 0;
        } else {
            return 1;
        }
    }
}

$username    =    "TimmehXXL";
echo "Is this true? " . var_between($username,4,20); 

This will result in:

Is this true? 1

Any comments?

[MentaL]

[FragFrog]

function var_between ($string, $min, $max) {
  return (strlen($string) >= $min && strlen($string) <= $max);
}

var_dump(var_between('bla', 5, 20));    // false
var_dump(var_between('blaaat', 5, 20)); // true 

There you go. Does in 1 line the same as what you do in 20 (but returns a proper boolean instead of 1 / 0).

Random note: it's not a parse error when the input doesn't follow the expected patterns, certainly not in a softtyped language like PHP. Parse errors occur when your source cannot be parsed and in fact already make sure your function has the valid amount of arguments. Just try calling your function with just 2 parameters: it never ever reaches even the first line, so your entire validation there will never run.

Also, suppose someone just wants to know if a parameter is a max of 10 chars:

var_between($string, 0, 10); 

Now your function echo's a silly parse error while it's a completely valid use of the function.

And on a final note for now: BABO!

(For those who have not had the pleasure of following a class by Frank Brokken: Blanks Around Binary Operators, ie, put some spaces between your conditions and echo's).

[timmeh39]

Lol yes. but i have to check for wrong input

And if you have 5,4 or 4,5 doesn't matter . in your script it has to be 4,5 else its almost always a fail

[Negata]

And if you have 5,4 or 4,5 doesn't matter . in your script it has to be 4,5 else its almost always a fail

That is the problem of the user, not the function. Of course, it's up to you to define the function so that either order will work, but it's a waste of time and resources. If you take the road of allowing different orders of parameters, why not take a step further and allow also the string to be any of the 3...

My point, it's just unnecessary. It's OK to assume whoever uses your function, knows how it's meant to be used. This is where documentation comes in. If you want to know more: [ame]http://en.wikipedia.org/wiki/Design_by_contract[/ame]

[s-p-n]

You're function is too programmer-centric, and not enough user-centric. I'm sure that point has already been put to light. When a user puts an empty value, or one that's too small/large, they don't want to see an error. They just want a little guidance on how to improve their values to match the rules of your form. If they see a message that says "PARSE ERROR!!", they might not know what to do, or worse, they'll think they broke something and may run off to a competing web-site. If the programmer using your function does it wrong, that's either their fault for not reading documentation, or your fault for not writing it clearly enough; (Or not writing it at all).

I'd do it procedurally. I don't see why you'd need a function for that anyhow.

Fear the Frog. Besides, it's very nice of him to point you in the right direction.

Anyway, why make a function when it's so easy to check?

$errMsg = (string) null;

//...

if(strlen($user)<$min && strlen($user)>$max)
{
    $errMsg .= '<p class="error">Your username must fall between "'.$min.'" &amp; "'.$max.'" characters.</p>';
}

//... 

if(strlen($errMsg)<1)
{
    mysql_query('...'); //Good
} else
{
    echo $errMsg; //Bad
} 

I could really care less how many lines it takes. That's not what measures CPU performance. I could overload any system with a single line if I wanted, so that's over-rated to a point. It's mostly knowing what functions do what, and how to cut back on heavier elements to reduce usage. Though line count does give something to work with when trying to simple-down code. Really, it's just for guidance. Most scripts can be improved by adding some spacing between the lines- Or at least it makes it easier to point out problems.

White-space is our friend.

Anyway, it's good you're experimenting with functions. Now try to make better use of them. ;)

For starters, try to find operations that start to repeat themselves. Those are what need functions the most

[timmeh39]

That was realy helpfull :D thanks

Well what you said about somethings that starts to repeat themselves :P well that is this i use it alot :)