What are the potential drawbacks of using mixed classes for processing and output in PHP?

Potential drawbacks of using mixed classes for processing and output in PHP include reduced code readability, increased complexity, and potential for errors due to mixing business logic with presentation logic. To solve this issue, it is recommended to separate the processing (business logic) and output (presentation logic) into separate classes or functions to improve code maintainability and readability.

class Processor {
    public function processData($data) {
        // Processing logic here
        return $processedData;
    }
}

class Output {
    public function displayData($data) {
        // Output logic here
    }
}

// Implementation
$processor = new Processor();
$output = new Output();

$data = // Get data from somewhere

$processedData = $processor->processData($data);
$output->displayData($processedData);