calculations

[assonitis]

dear friends,

how can I perform simple calculations with PHP.

I have a form and I want to validate a given number, and I have to perform some simple calculations in order to do it.

ty for the help

[Anon]

What calculations, specifically? PHP can do all the usual ones: addition, subtraction, multiplication, division, modulus. And there may be some functions to do calculations that are more task-specific.

Diego

[assonitis]

the number I want to validate is a nine digit number

lets say 123456789

what I want to to is

1 (2⁸⁾ +
2 (2⁷⁾ +
3 * (2⁶⁾ +
.....
and divide the result by 11

thanks

[Anon]

Ok, there's no power operator, but there is a power function. It's pow(), and you pass it the base and the exponent, e.g.:

pow(2,8) for 2⁸

What else do you need help with?

Diego

[assonitis]

and how can I tell php to do the following?

lets say again the number to be validated is $number=123456789

what I must do is
get the first digit
1 (2⁸⁾ +
get the second digit
2 (2⁷⁾ +
.
.
.
the number to be validated would be user input so I need a function to select the 1st digit and then the 2nd .....

million thanks

[Anon]

hi notis,

<?
$number="123456789";
$j = 8 ;
for($i=0;$i<strlen($number);$i++){
echo $product = $number[$i] * pow(2,$j);
$j--;
}
?>

is this what you wanted ?

if not please let me know and modify it.

ali

[Anon]

this is better to read =) :
<?
$number="123456789";
$j = 8 ;
for($i=0;$i<strlen($number);$i++){
$product = $number[$i] * pow(2,$j);

echo "$number[$i] * 2^$j: $product <br>";
$j--;
}
?>

ali

[assonitis]

hi ali,

unfortunately not, what i need is the following:

number is 123456789

I want this

(1(2⁸⁾⁾ + (2(2⁷⁾⁾ + (3*(2^6))....

but remember that 123456789 is not a fixed number, this is a user input and everytime will be a different one.

ty ali

[Anon]

and this ?:

<?
$number="123456789";
$j = 8 ;
for($i=0;$i<strlen($number);$i++){
$product[$i] = $number[$i] * pow(2,$j);
$j--;
}

$sum = 0;

for($i=0;$i<strlen($product);$i++){
$sum = $sum + $product[$i];
}
echo $sum;
?>

hope to get your point. if not let me try again.

ali

ps: making the $number user-defined is not so hard. I'll post the code, but plz tell me first if the functionality is correct ...

[Anon]

from ali's code you could have figured it out yourself...

<?
$number="123456789";
$product=0;
for($i=0;$i<strlen($number);$i++){
$product += $number[$i] * pow(2,8-$i);
}
print $product;
?>

Diego

[assonitis]

Dear ali and diego,

the most correct one is diego's (he got my question :-) )

<?
$number="123456789";
$product=0;
for($i=0;$i<strlen($number);$i++){
$product += $number[$i] * pow(2,8-$i);
}
print $product;
?>
this is the correct one, but I need one final correction.

I want to make the calculations up to the 8th digit. The proper result should be 1004.

And how can I make the $number be user-defined? the number comes from a form with name=afm

thanks guys for all the help

[Anon]

<?
$product=0;
for($i=0;$i<strlen($afm)&&$i<=7;$i++){
$product += $afm[$i] * pow(2,8-$i);
}
print $product;
?>

this code will do it. $i shoul be <= 7 because the value of $i in the beginning is 0 not 1.

making it user-defined:

<form name="something" action="script.php" method="post">
Enter Number: <input type="text" name="afm" value="">
<input type="submit">
</form>

that should do it ....

regards ali

[assonitis]

thank you ali and diego for all the help!