Basic Calculator in PHP

Name: Basic Calculator in PHP
Author: Nyaz

This is a very simple task, But it is really good to all you newbies out there.

PHP Code

<?php
if (!isset($_POST['submit']) && !isset($_POST['submit1']) && !isset($_POST['submit2']) && !isset($_POST['submit3'])) {
?>
<!DOCTYPE html>
<html>
    <head>
        <title>Zayne's Calculator</title>
    </head>
    <body>
        <h1>Zayne's Calculator</h1>
        <p>Welcome to the calculator version 2. I hope you can find any sums you want. Thank you.</p>
        <form method="post">
            <input type="text" name="text" placeholder="Enter first number">
            <input type="text" name="text1" placeholder="Enter second number">
            <br><br>
            <input type="submit" name="submit" value="Add">
            <input type="submit" name="submit1" value="Minus">
            <input type="submit" name="submit2" value="Divide">
            <input type="submit" name="submit3" value="Multiply">
        </form>
    </body>
</html>
<?php
} else {
    $num1 = isset($_POST['text']) ? $_POST['text'] : 0; // if not set, set 0
    $num2 = isset($_POST['text1']) ? $_POST['text1'] : 0; // if not set, set 0
 
    if (!is_numeric($num1) || !is_numeric($num2)) { // Check inputs are numbers
        echo "<p>Please enter valid numeric values.</p>";
        echo "<a href='calculator.php'>Back</a>";
        exit;
    }
 
    if (isset($_POST['submit'])) {
        $result = $num1 + $num2; // Addition
        echo "<p>$num1 + $num2 = $result</p>";
    } elseif (isset($_POST['submit1'])) {
        $result = $num1 - $num2; // Subtraction
        echo "<p>$num1 - $num2 = $result</p>";
    } elseif (isset($_POST['submit2'])) {
        if ($num2 == 0) { // Impossible
            echo "<p>Division by zero is not allowed.</p>";
        } else {
            $result = $num1 / $num2; // Division 
            echo "<p>$num1 / $num2 = $result</p>";
        }
    } elseif (isset($_POST['submit3'])) {
        $result = $num1 * $num2; // Multiplication
        echo "<p>$num1 * $num2 = $result</p>";
    }
 
    echo "<a href='index.php'>Back</a>";
}
?>

Notice I did not put $_POST['example'], I just did it the short way by putting a $ symbol in from of the html name. This can be done, However it is more secure to use $_POST.
In php, It is basically just a language that interacts with forms. You put the value of a textbox into a variable and php reads it from there. You can then insert anything you want.
An example of sticking a textbox into a variable is. <input type=text name=text> This will be $_POST['text']. Lots of beginners battle with that. From there when i converted those to variables i used alot of operators, which are used to transform the values of the variables.

Author:

Nyaz

Views:

2,340

Rating:

Posted on Monday 15^th October 2007 at 07:53 PM

Arudis

put this script anywhere you want the calculator you show lol

Posted on Monday 15^th October 2007 at 05:55 PM

rizwan1980pat
rizwan1980pat's Avatar

WHERE TO ENTER THIS SCRIPTS, SO THAT WE CAN MAKE USE OF IT.