What is the difference between convenience init vs init in swift, explicit examples better

Question

I am having troubles to understand the difference between both, or the purpose of the convenience init.

Answer 1

Here is a simply example, taken from the Apple Developer portal.

Basicly the designated initializer is the init(name: String), it ensure that all stored properties are initialized.

The init() convenience initializer, taking no argument, automaticly sets the value of name stored property to [Unnamed] by using the designated initializer.

class Food {
    let name: String

    // MARK: - designated initializer
    init(name: String) {
        self.name = name
    }

    // MARK: - convenience initializer
    convenience init() {
        self.init(name: "[Unnamed]")
    }
}

// MARK: - Examples
let food = Food(name: "Cheese") // name will be "Cheese"
let food = Food()               // name will be "[Unnamed]"

It is usefull, when you are dealing with large classes, with at least a few stored properties. I would recommend to read some more about optionals and inheritance at the Apple Developer portal.