Error vs Exception in PHP - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to throw an exception in PHP.

PHP

<?php
throw new [1]("Something went wrong!");
?>

Drag options to blanks, or click blank then click option'

AError

BException

CThrowable

DRuntimeException

Attempts:

3 left

💡 Hint

Common Mistakes

Using Error instead of Exception to throw an exception.

Forgetting the 'new' keyword before the class name.

The Exception class is used to throw exceptions in PHP.

2fill in blank

medium

Complete the code to catch an exception in PHP.

PHP

<?php
try {
    // code that may throw
} catch ([1] $e) {
    echo $e->getMessage();
}
?>

Drag options to blanks, or click blank then click option'

AException

BError

CThrowable

DRuntimeException

Attempts:

3 left

💡 Hint

Common Mistakes

Catching Error instead of Exception when handling exceptions.

Not specifying the exception variable in catch.

The catch block catches exceptions of type Exception or its subclasses.

3fill in blank

hard

Fix the error in the code to properly handle both errors and exceptions.

PHP

<?php
try {
    // code
} catch ([1] $e) {
    echo $e->getMessage();
}
?>

Drag options to blanks, or click blank then click option'

AException

BError

CThrowable

DErrorException

Attempts:

3 left

💡 Hint

Common Mistakes

Catching only Exception misses Errors.

Using Error alone does not catch Exceptions.

The Throwable interface allows catching both Error and Exception types.

4fill in blank

hard

Fill both blanks to create a custom exception class that extends the base Exception.

PHP

<?php
class MyException extends [1] {
    public function [2]() {
        return "Custom exception message.";
    }
}
?>

Drag options to blanks, or click blank then click option'

AException

B__construct

CgetMessage

DError

Attempts:

3 left

💡 Hint

Common Mistakes

Extending Error instead of Exception.

Overriding the constructor instead of getMessage.

Custom exceptions extend Exception and can override getMessage() to customize the message.

5fill in blank

hard

Fill all three blanks to throw and catch a custom exception properly.

PHP

<?php
class CustomError extends [1] {}

try {
    throw new [2]();
} catch ([3] $e) {
    echo "Caught custom error.";
}
?>

Drag options to blanks, or click blank then click option'

AException

BCustomError

DError

Attempts:

3 left

💡 Hint

Common Mistakes

Catching a different class than thrown.

Extending Error instead of Exception.

The custom exception class extends Exception. We throw an instance of CustomError and catch it by the same class.

Practice

1. Which statement best describes the difference between an Error and an Exception in PHP?

easy

A. Errors are serious problems that usually stop the script, while exceptions can be caught and handled.

B. Exceptions are more serious than errors and always stop the script immediately.

C. Errors can be caught with try-catch blocks, but exceptions cannot.

D. There is no difference; errors and exceptions are the same in PHP.

Solution

1. Step 1: Understand PHP error handling basics

   Errors usually indicate serious problems like syntax errors or memory issues that stop the script.

2. Step 2: Understand exceptions in PHP

   Exceptions are objects that can be caught and handled using try-catch blocks to keep the program running.

3. Final Answer:

   Errors are serious problems that usually stop the script, while exceptions can be caught and handled. -> Option A

4. Quick Check:

   Error stops script, Exception can be caught [OK]

Hint: Errors stop scripts; exceptions can be caught and handled [OK]

Common Mistakes:

• Thinking exceptions always stop the script
• Believing errors can be caught with try-catch
• Confusing errors and exceptions as identical

2. Which of the following is the correct syntax to catch an exception in PHP?

easy

A. try { /* code */ } catch (Exception $e) { /* handle */ }

B. catch (Exception $e) { /* handle */ } try { /* code */ }

C. try { /* code */ } except (Exception $e) { /* handle */ }

D. try: /* code */ catch (Exception $e): /* handle */ endtry;

Solution

1. Step 1: Recall PHP exception handling syntax

   PHP uses try { ... } catch (Exception $e) { ... } to handle exceptions.

2. Step 2: Identify correct syntax among options

   try { /* code */ } catch (Exception $e) { /* handle */ } matches the correct PHP syntax; others use wrong keywords or order.

3. Final Answer:

   try { /* code */ } catch (Exception $e) { /* handle */ } -> Option A

4. Quick Check:

   try-catch block syntax = try { /* code */ } catch (Exception $e) { /* handle */ } [OK]

Hint: Remember: try then catch with parentheses [OK]

Common Mistakes:

• Using 'except' instead of 'catch'
• Placing catch before try
• Using colon syntax which is invalid in PHP

3. What will be the output of the following PHP code?

try {
  throw new Exception('Oops!');
  echo 'No error';
} catch (Exception $e) {
  echo 'Caught: ' . $e->getMessage();
}

medium

A. Fatal error: Uncaught Exception

B. No error

C. Caught: Oops!

D. No output

Solution

1. Step 1: Understand the throw statement

   The code throws an Exception with message 'Oops!'. The line after throw is not executed.

2. Step 2: Catch block execution

   The catch block catches the Exception and echoes 'Caught: ' plus the message.

3. Final Answer:

   Caught: Oops! -> Option C

4. Quick Check:

   Exception thrown and caught outputs message [OK]

Hint: Throw stops try; catch runs and prints message [OK]

Common Mistakes:

• Expecting 'No error' to print
• Thinking throw causes fatal error without catch
• Ignoring that catch block runs after throw

4. Identify the error in this PHP code snippet:

try {
  echo 10 / 0;
} catch (Exception $e) {
  echo 'Error caught';
}

medium

A. Syntax error: missing semicolon after echo.

B. Division by zero error is not caught because it is an Error, not an Exception.

C. Catch block syntax is incorrect.

D. No error; code runs and prints 'Error caught'.

Solution

1. Step 1: Understand division by zero in PHP

   Division by zero triggers a fatal Error, not an Exception.

2. Step 2: Check catch block behavior

   Catch block only catches Exceptions, so the Error is not caught and script stops.

3. Final Answer:

   Division by zero error is not caught because it is an Error, not an Exception. -> Option B

4. Quick Check:

   Errors not caught by catch(Exception) [OK]

Hint: Errors like division by zero aren't caught by catch(Exception) [OK]

Common Mistakes:

• Assuming catch catches all errors
• Thinking division by zero throws Exception
• Ignoring difference between Error and Exception

5. You want to handle both Error and Exception in PHP to prevent your script from stopping unexpectedly. Which approach is best?

hard

A. Use set_exception_handler() to catch both errors and exceptions.

B. Only use try-catch blocks everywhere; errors will be caught automatically.

C. Ignore errors and exceptions; PHP will handle them internally.

D. Use try-catch for exceptions and set a custom error handler with set_error_handler() for errors.

Solution

1. Step 1: Understand handling exceptions

   Exceptions are handled with try-catch blocks to catch and manage them.

2. Step 2: Understand handling errors

   Errors are handled by setting a custom error handler using set_error_handler() to manage errors gracefully.

3. Final Answer:

   Use try-catch for exceptions and set a custom error handler with set_error_handler() for errors. -> Option D

4. Quick Check:

   Separate handlers for errors and exceptions [OK]

Hint: Use try-catch for exceptions, set_error_handler for errors [OK]

Common Mistakes:

• Expecting try-catch to catch all errors
• Ignoring errors leading to script termination
• Using set_exception_handler for errors