Declare strict_types directive in PHP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the declare(strict_types=1); directive do in PHP?

It enforces strict type checking for scalar type declarations in the file, meaning PHP will not perform type coercion and will throw a TypeError if types do not match exactly.

beginner

Where must the declare(strict_types=1); directive be placed in a PHP file?

It must be the very first statement in the PHP file, immediately after the opening <?php tag, before any other code or whitespace.

intermediate

True or False: The strict_types directive affects all files included or required by the current PHP file.

False. The strict_types directive applies only to the file where it is declared. Each file must declare it separately if strict typing is desired.

beginner

What happens if you call a function with a type mismatch when strict_types=1 is declared?

PHP throws a TypeError exception immediately instead of trying to convert the value to the expected type.

beginner

Example: How to declare strict types in a PHP file?

Place this at the top of your PHP file:<br>

<?php
declare(strict_types=1);
// Your code here

What is the correct way to enable strict typing in a PHP file?

A declare(strict_types=1); at the top of the file

B set_strict_types(true); anywhere in the file

C use strict_types(); inside functions

D enable_strict_types in php.ini only

The declare(strict_types=1); directive must be the first statement in the PHP file to enable strict typing.

If strict_types=1 is declared, what happens when you pass a float to a function expecting an int?

A PHP converts the float to int automatically

B PHP rounds the float silently

C PHP ignores the type and runs the function

D PHP throws a TypeError

With strict types enabled, PHP throws a TypeError if the argument type does not exactly match the declared type.

Does the strict_types directive affect included or required files automatically?

A Yes, it applies to all included files

B No, each file must declare it separately

C Only if included files are in the same directory

D Only if included files have the same namespace

Strict typing applies only to the file where declare(strict_types=1); is set.

Where must the declare(strict_types=1); statement appear in a PHP file?

A Immediately after the opening <code>&lt;?php</code> tag

B Anywhere before the first function call

C After all function definitions

D At the end of the file

It must be the very first statement after the opening PHP tag, before any other code.

What is the default behavior if strict_types is not declared?

A PHP throws errors on type mismatch

B PHP enforces strict type checking

C PHP silently converts types when possible

D PHP disables all type checking

By default, PHP uses weak typing and converts types automatically when possible.

Explain what the declare(strict_types=1); directive does in PHP and why you might want to use it.

Think about how PHP normally handles types and what changes with strict types.

Describe where and how to correctly place the declare(strict_types=1); directive in a PHP file.

Consider the file structure and PHP parsing rules.