What potential issues can arise when passing parameters in PHP?

One potential issue when passing parameters in PHP is that the number of parameters passed may not match the number expected by the function or method being called, resulting in a "Too few arguments" or "Too many arguments" error. To solve this, you can use default parameter values or use variable-length argument lists (variadic functions) to handle a variable number of arguments.

// Using default parameter values
function greet($name = "Guest") {
    echo "Hello, $name!";
}

greet(); // Output: Hello, Guest
greet("John"); // Output: Hello, John

// Using variable-length argument lists
function sum(...$numbers) {
    $total = 0;
    foreach ($numbers as $num) {
        $total += $num;
    }
    return $total;
}

echo sum(1, 2, 3); // Output: 6