Can't enter <input> operators number

Question

LastMitch

12 Years Ago

Hi

I'm been trying to enter numbers into the <input> so I can calculate Add - Subtract - Divide - Multiply.

This is the equations:

<?php
$number = 20;

$number += 10;
print "\$number += 10;<br /> The answer is <b>$number</b>. <br /><br />";

$number -= 12;
print "\$number -= 12;<br /> The answer is <b>$number</b>. <br /><br />";

$number *= 14;
print "\$number *= 14;<br /> The answer is <b>$number</b>. <br /><br />";

$number%= 16;
print "\$number %= 16;<br /> The answer is <b>$number</b>. <br /><br />";
?>

This is my form:

<html>
<body>

<form action="number.php" method="get">

Enter number: <input type="text" name="number" /><br /><br />

Enter number to Add: <input type="text" name="add" /><br /><br />

Enter number to Subtract: <input type="text" name="subtract" /><br /><br />

Enter number to multiply: <input type="text" name="multiply" /><br /><br />

Enter number to divide: <input type="text" name="divide" /><br /><br />

<input type="submit" value="Submit">

</form>

</body>
</html>

This is my number.php

$number = ' ';

$number += ' ';

$number -= ' ';

$number *= ' ';

$number %= ' ';

$number = isset($_GET['number']) ? (float)$_GET['number'] : 0;

This is what I got so far. I'm having problems calculating 4 different operator at once.

Any Suggestions and explanation will help. I appreciate it. Thanks!

mathematics php

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8 Replies
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21 Hours Discussion Span
Latest Post 12 Years Ago Latest Post by LastMitch

diafol

12 Years Ago

eval() will execute php for you, but this is really unsafe unless you lock down every possible input. Even then, I get really nervous with it.

I'm unclear as to what number.php is trying to show. You're setting number as a space and then you're performing a mathematical operations using a space as the next number?

Confused.

I'm assuming that you're building a calculator. If so, js is a far better vehicle IMO. Involving the server in every calculation may be tedious.

Bachu 45 Newbie Poster

12 Years Ago

In form.php

<html>
<body>

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

Enter number: <input type="text" name="number" /><br /><br />

Enter number to Add: <input type="text" name="add" /><br /><br />

Enter number to Subtract: <input type="text" name="subtract" /><br /><br />

Enter number to multiply: <input type="text" name="multiply" /><br /><br />

Enter number to divide: <input type="text" name="divide" /><br /><br />

<input type="submit" value="Submit">

</form>

</body>
</html>

In number.php

<?php
$number = (isset($_POST['number']) && $_POST['number']!="") ? $_POST['number'] : '0';
print "\$number = ".$number.";<br />";
$number += $_POST['add'];
print "\$number += ".$_POST['add'].";<br /> The answer is <b>$number</b>. <br /><br />";

$number -= $_POST['subtract'];
print "\$number -= ".$_POST['subtract'].";<br /> The answer is <b>$number</b>. <br /><br />";

$number *= $_POST['multiply'];
print "\$number *= ".$_POST['multiply'].";<br /> The answer is <b>$number</b>. <br /><br />";

$number/= $_POST['divide'];
print "\$number /= ".$_POST['divide'].";<br /> The answer is <b>$number</b>. <br /><br />";

?>

LastMitch commented: Thanks for the example! +5

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LastMitch · Answer 1 · 2012-10-04T00:24:31+00:00

@diafol

Thanks for the reply and explanation!

eval() will execute php for you, but this is really unsafe unless you lock down every possible input. Even then, I get really nervous with it.

I'm unclear as to what number.php is trying to show. You're setting number as a space and then you're performing a mathematical operations using a space as the next number?

Confused.

I'm assuming that you're building a calculator. If so, js is a far better vehicle IMO. Involving the server in every calculation may be tedious.

No, It's not a calculator. Sorry for the confusing.

This is the equations is not part of the form and number.php I used this as an outline for me to look at:

<?php

$number = 20;

$number += 10;
print "\$number += 10;<br /> The answer is <b>$number</b>. <br /><br />";

$number -= 12;
print "\$number -= 12;<br /> The answer is <b>$number</b>. <br /><br />";

$number *= 14;
print "\$number *= 14;<br /> The answer is <b>$number</b>. <br /><br />";

$number%= 16;
print "\$number %= 16;<br /> The answer is <b>$number</b>. <br /><br />";

?>

I figure another way. Instead all at once I separate it. I hope this make sense

LastMitch · Answer 2 · 2012-10-04T00:51:52+00:00

This is my form:

<html>
<body>

<form action="number.php" method="get">

Enter number: <input type="text" name="number" /><br /><br />

Enter number to Add: <input type="text" name="add" /><br /><br />

Enter number to Subtract: <input type="text" name="subtract" /><br /><br />

Enter number to multiply: <input type="text" name="multiply" /><br /><br />

Enter number to divide: <input type="text" name="divide" /><br /><br />

<input type="submit" value="Submit">

</form>

</body>
</html>

This my number.php

$number = ' ';
$number = isset($_GET['number']) ? (float)$_GET['number'] : 0;

$add = ' ';
$add = isset($_GET['add']) ? (float)$_GET['add'] : 0;

$subtract = ' ';
$subtract = isset($_GET['subtract']) ? (float)$_GET['subtract'] : 0;

$multiply = ' ';
$multiply = isset($_GET['multiply']) ? (float)$_GET['multiply'] : 0;

$divide = ' ';
$divide = isset($_GET['divide']) ? (float)$_GET['divide'] : 0;

$x = add;
$x = subtract;
$x = multiply;
$x = divide ;

switch ($x) {
    case 1: echo "add.php";
    break;
    case 2: echo "subtract.php";
    break;
    case 3: echo "multiply.php";
    break;
    case 4: echo "divide.php";
    break;
}

My add.php

echo "$number += $add;<br /> The answer is <b>$number</b>. <br />

My subtract.php

echo "$number -= $subtract;<br /> The answer is <b>$number</b>. <br />

My multiply.php

echo "$number *= $multiply;<br /> The answer is <b>$number</b>. <br />

My divide.php

echo "$number %= $divide;<br /> The answer is <b>$number</b>. <br />

OK, My initial plan was to follow the equation all at once but then I realized it will be hard. So I separate each input by using Case. I hope this make sense.

Any Suggestions and explanation will help. I appreciate it. Thanks!

diafol · Answer 3 · 2012-10-04T06:53:01+00:00

I think you've over-engineered this. Can't reply now - going to work, but will come back if nobody else replies.

LastMitch · Answer 4 · 2012-10-04T18:09:06+00:00

@diafol

I think you've over-engineered this. Can't reply now - going to work, but will come back if nobody else replies.

You might be right about me overthinking a simple example.

LastMitch · Answer 5 · 2012-10-04T18:09:42+00:00

@Bachov Varghese

Thanks for the reply and example! I will test it.

LastMitch · Answer 6 · 2012-10-04T18:12:11+00:00

@Bachov Varghese

Thanks for the example! It works!