How can PHP developers troubleshoot issues with custom functions not working as expected in their code?

To troubleshoot issues with custom functions not working as expected in PHP, developers can start by checking for syntax errors, ensuring the function is being called correctly with the right parameters, and verifying that the function is returning the expected output. They can also use debugging tools like var_dump() or echo statements to track the flow of the code and see where the issue might be occurring.

// Example code snippet demonstrating how to troubleshoot custom function issues in PHP

// Define a custom function
function addNumbers($num1, $num2) {
    return $num1 + $num2;
}

// Call the function with correct parameters
$result = addNumbers(5, 3);

// Check the output
echo $result; // Output should be 8