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iOS

Posted by jon kelson
jon kelson
5,149 Points

Hi what's the difference between functions and methods in terms of where they are positioned?

Hi what's the difference between functions and methods in swift in terms of where they are positioned?

1 Answer

Michael Hulet
Michael Hulet
47,913 Points

A function is declared at the global scope and can run without making an instance of a class, struct, or enum, but a method is declared on a class, struct, or enum and you have to instantiate one before you can use it. For example:

// This is a function
func add(left: Int, right: Int) -> Int{
    return left + right
}

//It can be called like this
add(left: 5, right: 10) // returns 15

struct Number{
    let value: Int
    //This is a method
    func add(other: Int) -> Number{
        return Number(value: self.value + other)
    }
    //Inits are also methods
    init(value: Int){
        self.value = value
    }
}

//They can be called like this
let first = Number(value: 5)
let result = first.add(other: 10)
result.value // is 15
jon kelson
jon kelson
5,149 Points

Thank you Michael very much . I understand those now . Just one last quick question if that's ok . Q. , so why don't we just use one or the other , methods or functions . Is there advantages one over the other . Thanks

Michael Hulet
Michael Hulet
47,913 Points

That's quite an argument that really depends on who you ask (functional vs. object-oriented paradigms). Apple's frameworks are designed to be object-oriented, and really wants you to favor methods over functions, and that's what Treehouse teaches

jon kelson
jon kelson
5,149 Points

Ok so I guess you can use either , either inside your class etc or outside they do the same thing , but preferrably use methods . Many thanks for a great answer Michael ?