Question about functions?

Sillysoft

How would you return values? Meaning if I did a function:

function This () {

sqlquery
$num=mysql_num_rows(w);
return $num;

}

nothing happens. Meaning it doesnt return anything. Also if I try to echo out a value from a function instead of putting it in the place where i placed the function in the webpage, it echos it at the very top

so like

echo "this";

would return on the page

this
rest of html code

Also if I do a loop in a function and try a return it just returns the first value and stops. Please help 🙁

simon622

If you could include your code, Flush out any html and
we can have a look to see what is happening.
Cheers.

Sillysoft

function GETYPE() {

$gettype = "SELECT * FROM tbl";
$getresult = mysql_query($gettype);
$getrows = mysql_num_rows($getresult);
$start = 0;

while ($start < $getrows) {

$therow = mysql_result($getresult,$getstart,'therow');
$showtype = "<option value=\"$type\">$type</option>";
return $showtype;
++$getstart;

}

This is a example function which is similiar to what i am using. So when I return showtype it just gives me the first entry and that is that. now if I try to echo $showtype it shows all the entries but not in the place it needs to be. It shows at the very top of the page above the html page.

I used a template class for the html. Meaning I create the template, import it and replace {INFORMATION} with the proper information I choose from the class

Hope this helps

simon622

Right,

You are trying to return more than one item from your function.
Functions only allow you to return one of whatever,

eg; variable, array, object, connection etc etc.

You are trying to return the following;

$showtype = "<option value=\"$type\">$type</option>"; 
return $showtype;

for every occurance in the loop.

You should try to build your output and then return it all at the end of the loop,

something like eg.

while ($start < $getrows) { 
$therow = mysql_result($getresult,$getstart,'therow'); 
$showtype = $showtype."<option value=\"$type\">$type</option>"; 
++$getstart; 
} 
return $showtype;

This adds to the $showtype variable on every loop, and then returns $showtype at the end. Or you could build an array within the loop and return that.

Hope this helps.

Sillysoft

Wow! Thanks that worked. Hmm.. Another question, sorry if I am bothering you, can you start a session in a class and how would you go about passing it page to page? I know I would need to include the class file on every page. But when I try this:


class test { 

function GetSession() { 

session_start(); 
session_register('whatever'); 

} 

}

the session does not come out nor the registered variable. So how do I start and pass a session in a class/function?

I really appreciate the help!

simon622

You need to make sure your class is finalised, and then return the session from the class to the calling page.

EG;

class SessionHandler(){

var sess = "";

function SessionHandler(){
//Constructor
$this->startSess();
}

function startSess(){
$this->sess = session_start();
}

function getSession(){
return $this->sess;
}

function regVar($varIn){
session_register($varIn);
}

function getVars($key){
return HTTP_SESSION_VARS[$key];
}

}

I havnt tested this but it should be alright.
I personally have a complete session handling class with all function I require as returned PHP functions.

Hope this might help

simon622

Sorry I forgot to explain it....

Well basically, as im sure you know, a class encapsulates functionality, it is a 'black box' program. You should set your session variables as instance variables and access them through the class. This encorages data-hiding.

Think of it as a wrapper around the session. To access the session variables, you do it through the instance variables.

You should have a complete set of accessor methods and use them, eg to set a session variable use a setter method, eg, setName('simon'); and then in the object method setName(),
register the variable as a session variable. The getters then access the variables using the global session array HTTP_SESSION_VARS[].

The class above will need adding to, you should initalise all you session variables as instance variables.

Hope this explains the methodology,

Sillysoft

thanks for the info! Last question if you dont mind.

Can you explain return?

When I type in return in a function does that mean it stops what it is doing and returns the ownership back to the main page? Meaning it jumps out of the class?

also when I type in return $variable does it return the value of that variable to the browser outside of the class?

so if i do


class This {

function This () {  //constructor

$this=that;
return $this;

}

}

What does it do? Return the value of $this and prints it out? Also sometimes it returns it sometimes it doesnt. Is it because I have return $this in the wrong place?

Also when I do an echo instead of a return it does echo whatever I tell it to echo, but it puts it at the top of the html document instead of where i embedded the script in the html doc.


class This {

function This () {  //constructor

$this=that;
echo $this;

}

}

It returns "that" but when i bring up the page it does

that
..then the html page

where i want it to go $this;

Can you tell me what Im doing wrong?

bernouli

also when I type in return $variable does it return the value of that variable to the browser outside of the class?

return means return back the value to the variable, which call the function. It depends what the function does, when something inside the function echoed, it will be printed in the browser.

for example

function This () { 

$this= 5;
return $this;

}

$a = This() ; // $a = 5

The example doesnt print the $a in browser, to do that you must extra type echo $a after the function.

another example,

function This () {

$this= 5;
echo $this;

}

$a = This();
//not allowed, because This() doesnt return anything to $a

but you can use simple
This();
and "5" will be printed directly to the browser

simon622

OK, I'll try and clear this all up.

WHAT IS A FUNCTION?
A function performs a defined task, often one that is required to be performed more than once, and is initalised using a function call.
eg;

function helloWorld(){
echo "Hello World";
}

When called with;

helloWorld();

Will simply output 'Hello World' into the calling script.
However, if we wanted to perform a maths function, e.g add 1 to whatever was passed through a function we would;

function Increment($parameterIn)
{
$parameter = $parameterIn + 1;
return $parameter;
}

If we called that function, like so..

$parameter = "2";
$Incremented_parameter = Increment($parameter);
echo "$Incremented_parameter";

It would print out 3.
The return value, is passed to "$Incremented_parameter".
It is also good to remember the scope of the variables, whether they are global scope or function scope.

A function accepts COPIES of variables as paramters, no the actual variable, therefore if you did this;

function wontWork($myvariable){
$myvariable + 1;
}

then in the calling script,
you did

wontWork(4);

Nothing would happen and the value in the calling script would still be 4.

Think of a function of a separate program on its own, it knows nothing, you have to pass it something, let it do it's own job and give you something back.

Hope this helps

Sillysoft

Ok I am including the class file into the php main doc. So where would I type

$a = This() ; // $a = 5

That be in the function? Or when I call the object in the main php document? So your saying you have to assign the returned value to a variable and then echo it out?

Sillysoft

Ack. Ok so is accessing a single function different from accessing a function inside a class?

Ok so basically you do this

$run = new ClassName();

That opens the class and makes all the functions available right? So from here on out if I wanted to access a function inside that class I would have to use the variable $run to get back into the class and access the functions correct?

So $run->FunctionName(); correct?

So when FunctionName(); gets executed and inside the function I do this:

function $GetThis() {

$this=5;
return $this;

}

So the function returns $this back to the main page right? This is where Im losing it for some reason. It is starting to make sense but still unsure.

I do appreciate the help btw.

bernouli

see, its not quite hard understanding classes and function right?
but assuming your class has constructor, then your codes here are right

$run = new ClassName();

but when you have no constructor, simple use this

$run = new ClassName;

but when your function have return inside, you must deliver the value to other variable eg

$a = $run->GetThis();

simon622

Yes, using object methods you have to create the object first.

You are accessing the object methods correctly using $myInstance->myFunction();

INSIDE the class, you refer to all instance methods and variables using $this->attribute or $this->function().
If you wanted to return a sum from inside a class into a main script; do this;

class Sum(){
function addOne($parameterIn){
$parameter = $parameterIn +1;
return $parameter;
}
}

//MAIN PAGE....

$sum = new Sum();
$one = 1; //Global Variable
$two = $sum->addOne($one);

$two would now equal 2. $one would still equal 1. The value of
$one + 1 is assigned to the global variable $two.

Sillysoft

OMG I think I got it and now it seems so simple.

So basically just assign the function to a variable and echo out that variable so if it does return an error it will return that error where you embedded it in the document! Sweet I will definently bookmark this page

You guys really helped me out! Still have a ways to go but I do see a little beam of light up ahead in this dark tunnel 🙂

Sillysoft

Man I was trying not to ask another question but man you guys are good. 🙂

Hate to pass up this oppertunity. Right now the web apps I make work but dont think they are pretty sophisticated/secure. The way I create a web template is:

make the main template and include a variable in the place I want the dynamic pages to come up.

<? include $thispage; ?>

Then I have a switch that takes the value of the GET variable and then tells it what $thispage will be. So

When you click it the switch then does this

switch ($route) {

case "main":
$thispage=files/thispage.php;
break;

}

So then the page shows up. Obviously this is bulky and not secure. Though the main page is secure where you include the files, you can easily access the other files in the files directory bypassing the sessions and what not.

So is there a way to better this? Is this a common way of doing it? I did create a class that takes a template and then replaces any thing that has {THIS} around it with the dynamic info it pulls from the class. But dunno if that itself is a waste of time.

If you can either let me know of a better, easier, more secure way of making web templates or can point me to a good tutorial it would be much appreciated

I ask these questions because I asked them before on here and never got a reply.

simon622

No Porblem mate, glad we could be of some help.

Any problems, drop us a message.

Sillysoft

Woops posted right after me. please read message at top 🙂

simon622

Why not try using some pear stuff.

Pear HTML Templates

Theres no sense re-inventing the wheel. There is some really good packages in there.

bernouli

to save the switch case, you can simple type

include($route.".php");

and the page,depends on $route should be automatically included