How can PHP constants be used effectively to avoid issues with variable visibility, as suggested in the thread?

Using PHP constants can help avoid issues with variable visibility by ensuring that the value remains constant throughout the code execution. Constants are accessible globally within the script, making them a reliable choice for storing values that should not be changed. By defining important values as constants, you can prevent accidental changes or conflicts with variable scope. 

<?php

define('PI', 3.14);

function calculateArea($radius) {
    return PI * $radius * $radius;
}

echo calculateArea(5); // Output: 78.5

?>

Keywords

PHP constants variable visibility scope global keyword define()

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