What is the main purpose of the `init` block in Kotlin?

The init block in Kotlin serves to initialize properties when a class instance is created. When a class is instantiated, the code within the init block executes immediately after the primary constructor and can be used to set initial values for properties or perform any setup that the class requires. This allows developers to centralize initialization logic, making it easier to manage and understand how objects are initialized.

By utilizing the init block, properties of the class can be assigned values based on constructor parameters or fixed data, ensuring that every instance of the class starts in a valid state before any further actions are taken. It effectively acts as a constructor body, where you can write additional logic beyond simple property declarations. This feature enhances the object-oriented nature of Kotlin by ensuring encapsulation and control over the initialization process.