Exceptions in PHP

In PHP, exceptions provide a powerful way to handle errors and unusual conditions in a controlled manner. Rather than letting errors crash your program, you can catch them and decide how to respond.

? What is an Exception?

An exception is an object that describes an error or unexpected behavior in a program. It can be "thrown" and "caught" using try, catch, and throw statements.

? Basic Exception Handling Syntax

<?phptry {    // Code that might throw an exception    throw new Exception("Something went wrong!");} catch (Exception $e) {    // Code to handle the exception    echo "Caught exception: " . $e->getMessage();}?>

? Explanation:

• try block: Code that might cause an exception.

• throw: Used to throw an exception manually.

• catch: Catches and handles the thrown exception.

? Example with Division by Zero

<?phpfunction divide($a, $b) {    if ($b == 0) {        throw new Exception("Cannot divide by zero.");    }    return $a / $b;}try {    echo divide(10, 0);} catch (Exception $e) {    echo "Error: " . $e->getMessage();}?>

Output:

Error: Cannot divide by zero.

? Custom Exception Class

You can also define your own custom exception class:

<?phpclass MyException extends Exception {    public function errorMessage() {        return "Custom Error: " . $this->getMessage();    }}try {    throw new MyException("This is a custom exception.");} catch (MyException $e) {    echo $e->errorMessage();}?>

? Multiple Catch Blocks (PHP 7+)

<?phptry {    // code that might throw multiple types of exceptions} catch (InvalidArgumentException $e) {    echo "Invalid argument: " . $e->getMessage();} catch (Exception $e) {    echo "General error: " . $e->getMessage();}?>

? Finally Block

The finally block executes regardless of whether an exception was thrown or not.

<?phptry {    echo "Trying...<br>";    throw new Exception("Something failed!");} catch (Exception $e) {    echo "Caught: " . $e->getMessage() . "<br>";} finally {    echo "Always runs this.";}?>

? Built-in Exception Methods

? Best Practices

• Use exceptions for exceptional conditions (not for flow control).

• Always catch exceptions to avoid unhandled fatal errors.

• Log exception details for debugging.