Error vs Exception in PHP - Visual Side-by-Side Comparison

Concept Flow - Error vs Exception in PHP

Start PHP Script

↓

Code Runs

↓

Error Occurs?

No→Continue Execution

Yes↓

Is it Exception?

No→Error Handling (Fatal or Warning)

Yes↓

Exception Thrown

↓

Catch Exception?

No→Script Stops

Yes↓

Handle Exception

↓

Continue or Exit Gracefully

PHP runs code and checks for errors. Errors may stop the script or warn. Exceptions can be caught and handled to keep script running.

Execution Sample

PHP

<?php
try {
  throw new Exception('Oops!');
} catch (Exception $e) {
  echo $e->getMessage();
}
?>

This code throws an exception and catches it to print the message instead of stopping the script.

Execution Table

Step	Action	Evaluation	Result
1	Start script	No error or exception yet	Script running
2	Enter try block	No error	Inside try
3	Throw Exception	Exception('Oops!') created	Exception thrown
4	Catch Exception?	Yes, catch block matches Exception	Catch block entered
5	Execute catch block	$e->getMessage() returns 'Oops!'	Output: Oops!
6	End script	No unhandled errors or exceptions	Script ends normally

💡 Script ends normally after handling the exception.

Variable Tracker

Variable	Start	After Step 3	After Step 4	Final
$e	undefined	Exception object created	Exception object caught	Exception object used in catch

Key Moments - 3 Insights

Why doesn't the script stop when an exception is thrown?

Because the exception is caught in the catch block (see execution_table step 4), so the script handles it and continues.

What happens if an error occurs but is not an exception?

PHP may stop the script or show a warning depending on error type, since errors are not caught like exceptions (see concept_flow step 'Is it Exception? No').

Can exceptions be thrown without try-catch blocks?

Yes, but if not caught, the script stops with a fatal error (see concept_flow step 'Catch Exception? No').

Visual Quiz - 3 Questions

Look at the execution_table, what is the output at step 5?

A Fatal error

B Oops!

C No output

D Exception object

💡 Hint

Check the 'Result' column at step 5 in execution_table.

At which step does the exception get caught?

A Step 3

B Step 5

C Step 4

D Step 6

💡 Hint

Look for 'Catch block entered' in the 'Result' column.

If the catch block was missing, what would happen?

A Script stops with fatal error

B Exception is ignored

C Script continues normally

D Error warning shown but script continues

💡 Hint

Refer to concept_flow step 'Catch Exception? No --> Script Stops'.

Concept Snapshot

PHP Errors and Exceptions:
- Errors are problems PHP detects (fatal, warning, notice).
- Exceptions are special errors you can throw and catch.
- Use try { ... } catch (Exception $e) { ... } to handle exceptions.
- Uncaught exceptions stop the script.
- Errors may stop or warn depending on severity.

Full Transcript

This visual execution shows how PHP handles errors and exceptions. The script starts and runs code inside a try block. When an exception is thrown, PHP looks for a matching catch block. If found, it runs the catch block code, allowing the script to continue. If no catch block exists, the script stops with a fatal error. Errors differ from exceptions; they may stop the script or show warnings depending on type. Exceptions provide a way to handle problems gracefully in PHP code.