# PHP Basics (Laravel)

> Variables & constants, types, arrays, control flow, functions, namespaces, error handling

- 25 interview questions
- Junior
- [Interview Questions: Laravel](https://sharpskill.dev/en/technologies/laravel/interview-questions.md)

## 1. What is the main difference between a variable and a constant in PHP?

**Answer**

A constant is defined once and its value cannot be modified afterwards, unlike a variable whose value can change at any time during script execution. Constants are declared with define() or const and do not require the $ symbol before their name. They are particularly useful for storing configuration values that should never change, such as file paths, base URLs, or API keys.

## 2. How to correctly declare a variable in PHP?

**Answer**

In PHP, all variables must start with the $ symbol followed by the variable name. The name can contain letters, numbers, and underscores, but must start with a letter or underscore. PHP is case-sensitive for variable names, meaning $name and $Name are two different variables. It is not necessary to declare the type when creating a variable because PHP is a dynamically typed language.

## 3. What is the data type returned by the following expression: 5 + 3.2?

**Answer**

When an arithmetic operation involves an integer and a floating-point number, PHP automatically converts the result to a float to preserve decimal precision. This automatic type conversion is called type juggling or type coercion. In this example, 5 is an integer and 3.2 is a float, so the result 8.2 will automatically be a float. This is important behavior to understand to avoid calculation errors in financial or scientific applications.

## 22 more questions available

- Which function checks if a variable is defined and not null?
- How to declare a class constant in PHP?

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## Other Laravel interview topics

- [PHP OOP Essentials](https://sharpskill.dev/en/technologies/laravel/interview-questions/php-oop-essentials.md): 20 questions, Junior
- [Composer & Autoloading](https://sharpskill.dev/en/technologies/laravel/interview-questions/composer-autoloading.md): 18 questions, Junior
- [Laravel Fundamentals](https://sharpskill.dev/en/technologies/laravel/interview-questions/laravel-fundamentals.md): 20 questions, Junior
- [Laravel Routing](https://sharpskill.dev/en/technologies/laravel/interview-questions/laravel-routing.md): 20 questions, Junior
- [Blade Templates](https://sharpskill.dev/en/technologies/laravel/interview-questions/blade-templates.md): 18 questions, Junior
- [Request & Response](https://sharpskill.dev/en/technologies/laravel/interview-questions/request-response.md): 20 questions, Junior
- [Eloquent ORM Basics](https://sharpskill.dev/en/technologies/laravel/interview-questions/eloquent-orm-basics.md): 22 questions, Junior
- [Eloquent Relationships](https://sharpskill.dev/en/technologies/laravel/interview-questions/eloquent-relationships.md): 25 questions, Mid-Level
- [Migrations & Schema Builder](https://sharpskill.dev/en/technologies/laravel/interview-questions/database-migrations.md): 20 questions, Mid-Level
- [Validation & Forms](https://sharpskill.dev/en/technologies/laravel/interview-questions/validation-forms.md): 22 questions, Mid-Level
- [Authentication](https://sharpskill.dev/en/technologies/laravel/interview-questions/authentication.md): 20 questions, Mid-Level
- [Authorization & Policies](https://sharpskill.dev/en/technologies/laravel/interview-questions/authorization-policies.md): 18 questions, Mid-Level
- [API Resources & Authentication](https://sharpskill.dev/en/technologies/laravel/interview-questions/api-resources-authentication.md): 26 questions, Mid-Level
- [Middleware](https://sharpskill.dev/en/technologies/laravel/interview-questions/middleware.md): 18 questions, Mid-Level
- [Service Container & DI](https://sharpskill.dev/en/technologies/laravel/interview-questions/service-container-di.md): 20 questions, Mid-Level
- [Queues & Jobs](https://sharpskill.dev/en/technologies/laravel/interview-questions/queues-jobs.md): 22 questions, Mid-Level
- [Events & Listeners](https://sharpskill.dev/en/technologies/laravel/interview-questions/events-listeners.md): 18 questions, Mid-Level
- [Notifications & Mail](https://sharpskill.dev/en/technologies/laravel/interview-questions/notifications-mail.md): 20 questions, Mid-Level
- [File Storage](https://sharpskill.dev/en/technologies/laravel/interview-questions/file-storage.md): 18 questions, Mid-Level
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- [Deployment & DevOps](https://sharpskill.dev/en/technologies/laravel/interview-questions/deployment-devops.md): 20 questions, Senior

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