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iOS Object-Oriented Swift 2.0 Complex Data Structures Instance Methods

Posted by swiftfun
swiftfun
4,039 Points

Parameters in a method

Two questions:

1- Is any function inside a struct necessarily called a Method? Do we no longer call them Functions? Please clarify when do we call it Method and when do we call them Functions

2- Do we ever use parameters in a func which is inside a struct? Since the struct itself is a blueprint and later on we will use it to input (in this case first and last name) will we ever need to use parameters in a function, or will it always be empty () ?

struct Person {
    let firstName: String
    let lastName: String

    func getFullName() -> String { // Are func parameters always empty when inside a struct?
        return "\(firstName) \(lastName)"
    }
}

let aPerson = Person(firstName: "John", lastName: "Doe")
let fullName = aPerson.getFullName()

4 Answers

Welby Obeng
Welby Obeng
20,340 Points
Welby Obeng
Welby Obeng
20,340 Points

  1. Any function associated with class or structure is called a method. If it’s not associated with class or structure it’s called a function. A function is a piece of code that is called by name, whereas a method is a piece of code that is called by name that is associated with an object (instance of class or structure). It can be passed data to operate on (ie. the parameters) and can optionally return data (the return value).

  2. You can provide method parameters inside a class or structure.

swiftfun
swiftfun
4,039 Points
swiftfun
swiftfun
4,039 Points

Thank you Welby,

Why would you include method parameters in a struct instead of using stored properties in the struct?

I see you could include "age" in the previous example as a method parameter, wouldn't it be more convenient to include that in a struct? Just trying to think of an example in a functioning app, still learning the theory and not quite sure about how everything will work out in an app. When would you use structs or functions?

struct Person {
    let firstName: String
    let lastName: String

    func getFullName(age: Int) -> String {
        return "\(firstName) \(lastName) is \(age) years old."
    }
}

let aPerson = Person(firstName: "John", lastName: "Doe")
let fullName = aPerson.getFullName(3)
Welby Obeng
Welby Obeng
20,340 Points
Welby Obeng
Welby Obeng
20,340 Points

Good question, let's say someone wants a full name with spacing and not with spacing...

if getFullName method takes in a bool called WithSpacing, that can be set true or false, I can have an if statement that check if WithSpacing is true and return fullname with spacing, if it's false I can return full name without spacing...

You wouldn't want to set WithSpacing variable as a property of the struct object because it's really pretaining to the getFullName method

swiftfun
swiftfun
4,039 Points
swiftfun
swiftfun
4,039 Points

Makes sense. Hopefully you or someone else could provide more insight and examples