What are the differences between functions and methods in Swift?

Question

I always thought functions and methods were the same, until I was learning Swift through the \"Swift Programming Language\" eBook. I found out that I cannot use greet(

Answer 1

Well, @Ricky's answer says it pretty much. I was confused what exactly they are. So here is my thought:

Functions could be defined outside of classes or inside of classes/structs/enums, while Methods have to be defined inside of and part of classes/structs/enums.

We could define a Function outside of any Type's definition and could use it within Methods of any Type's definition.

Just my understanding and illustration here, hope this helps someone else or you may edit if you feel there is an improvement needed OR let me know if anything is wrong:

//This is a Function which prints a greeting message based on the category defined in an 'enum'
func greet(yourName name: String, category: GreetingsCategory) {
    switch  category {
        case .Person:
            print("Hello, " + name + " Today is Tuesday")
        case .Vehicle:
            print("Hello, " + name + " your Vehicle is a Car")
    }
}

//This is an 'enum' for greetings categories
enum GreetingsCategory: String {
    case Person
    case Vehicle
}

//Type: Person
class Person {

    //This is a method which acts only on Person type
    func personGreeting() {
        greet(yourName: "Santosh", category: .Person)
    }
}

//Type: Vehicle
class Vehicle {

    //This is a method which acts only on Vehicle type
    func vehicleGreeting() {
        greet(yourName: "Santosh", category: .Vehicle)
    }
}

//Now making use of our Function defined above by calling methods of defferent types.
let aPerson = Person()
aPerson.personGreeting()
//prints : Hello, Santosh Today is Tuesday

let aVehicle = Vehicle()
aVehicle.vehicleGreeting()
//prints: Hello, Santosh your Vehicle is a Car

//We can also call the above function directly
greet(yourName: "Santosh", category: .Person)