[_matt]

I am learning PHP and made this little form to see if I am actually using the code correctly. It works but is it correct?

PHP Code:

<form action="index.php" method="post">

<input type="text" value="" name="age" />

<input name="submit" type="submit" value="submit" /></form>

<?PHP

$age = $_POST['age'];

if($age == ""){

    echo "Enter a age to test";

    }elseif($age >20){

    echo "$age is greater then 20";

    }elseif ($age <20){

    echo "$age is less then 20";

    }

?>

[bizzar528]

It is correct, but in a more complicated script, that won't work well.
I would start by making the form one file, and the php processing another. Yes, you can do it all in one file, but for learning, it's probably best to split them up. Make the form index.php and move the php to it's own file. Let's call it process.php. Then, change the action in your form to "process.php".

Also, there should be an else. What if I entered some word. Like "blah" into your form. blah isn't < or > 20, so what should the form do with it. Once again, this doesn't matter in a simple script, but when you learn more advanced functions, you'll be happy you took the time to deal with whatifs.

[_matt]

Agreed with using 2 files. THis is just for testing. But for restricting a-z and only allowing numbers, does this look correct?

PHP Code:

<form action="index.php" method="post">

  <input type="text" value="" name="age" />

  <input name="submit" type="submit" value="submit" />

</form>

<?PHP

$age = $_POST['age'];

function check_age($age){

  if(!preg_match("/[^0-9]+$/s",$age))

  return TRUE;

  else

  return FALSE;

}

if(!check_age($age))

{

  echo "Please only enter numbers";

  $error++; 

}

if($error == 0)

if($age == ""){

    echo "Enter a age to test";

    }elseif($age >20){

    echo "$age is greater then 20";

    }elseif ($age <20){

    echo "$age is less then 20";

}

?>

[Nico]

I'd use:

PHP Code:

if(preg_match("/^[0-9]+$/", $age)) 

[_matt]

Nico,

Why remove the

PHP Code:

! 

I thought

PHP Code:

! = not or null 

[grafman]

_matt,

bizzar528 makes a very good statement about handling the default condition. You can use switch statements as well to reduce the complexity that you get with lots of "if" statements.

If you find an exception either die, return, or exit right away and don't risk continued execution. If you have a function or class method that gives a return, ALWAYS handle the return. A little more code, but it saves hunting for strange results.

Don't forget to handle the condition where age is exactly 20. You could change one of the not equal cases to >= or <= as well as have the equivalence comparison.

Nico,

don't forget the perl regex predefined sequences! \d must be numeric \must be alpha.

PHP Code:

<?PHP



$age = $_POST['age'];

// validate that your varialbe is set before

// passing it to your function.  Probably this

// would be validated on the browser side with javascript

if($age)

  check_age($age);

else

  print("Enter an age to process");



function check_age($age)

{

  // checks to see if there are any alpha 

  // characters in string

  if(preg_match('/\D/',$age))

    die("digits only");



  // another way to check for digits

  // will work with decimals if you cast age

  if(preg_match('/\d/',$age))

  {

    if($age > 20)

      print "Age is greater than 20";

    elseif($age == 20)

      print "Age is 20";

    else

      print "Age is less than 20";

  }

  else

  {

    print "Should never get here but its nice to have";

  }

}

?

[UnrealEd]

the fastest way to check if the string only contains digits is using the ctype_digit function, like this:

PHP Code:

if(ctype_digit($_POST['age'])){

// it's a digit

}else{

// it's something else

} 

UnrealEd