PHP Program to check if a Number is Postive or Negative

To check if a number is positive or negative in PHP using an HTML form, you can create a simple web page that takes input from the user through a form and then processes that input in PHP. Here’s an example of how you can do this:

1. Create an HTML form (index.html):

   • <!DOCTYPE html>
     <html>
     <head>
         <title>Positive/Negative Number Checker</title>
     </head>
     <body>
         <h1>Positive/Negative Number Checker</h1>
         <form method="post" action="check_number.php">
             <label for="number">Enter a number: </label>
             <input type="number" name="number" id="number" required>
             <button type="submit">Check</button>
         </form>
     </body>
     </html>
     

2. Create a PHP script (check_number.php) to process the form input and check if the number is positive or negative:

   • <?php
     if ($_SERVER["REQUEST_METHOD"] === "POST") {
         // Get the user input from the form
         $number = $_POST["number"];
     
         // Check if the number is positive, negative, or zero
         if ($number > 0) {
             $result = "The number $number is positive.";
         } elseif ($number < 0) {
             $result = "The number $number is negative.";
         } else {
             $result = "The number $number is zero.";
         }
     }
     ?>
     
     <!DOCTYPE html>
     <html>
     <head>
         <title>Positive/Negative Number Checker</title>
     </head>
     <body>
         <h1>Result</h1>
         <?php if (isset($result)) : ?>
             <p><?php echo $result; ?></p>
         <?php else : ?>
             <p>No input received.</p>
         <?php endif; ?>
         <a href="index.html">Go back</a>
     </body>
     </html>
     

Here’s how this works:

• The index.html file contains a form with an input field where the user can enter a number. When the user submits the form, it sends the input to the check_number.php script for processing.
• In check_number.php, we check if the request method is POST, which indicates that the form has been submitted. We retrieve the user input using $_POST["number"].
• We then use PHP to check if the number is positive, negative, or zero, and store the result in the $result variable.
• Finally, we display the result on the web page along with a link to go back to the input form.

To use this code, save the HTML code in an index.html file and the PHP code in a check_number.php file in the same directory. Open the index.html file in your web browser, enter a number in the form, and click “Check” to see the result.