Why does a function call require the parameter name in Swift?

Question

I have this Function in a class:

func multiply(factor1:Int, factor2:Int) -> Int{
    return factor1 * factor2
}

I try to call the functi

Answer 1

Because your "multiply" function is a method, and like Objective-c, the parameters in methods are part of the name.

For example you can do this.

class Calculator {

    func multiply(factor1:Int, factor2:Int) -> Int{
        return factor1 * factor2
    }

    func multiply(factor1:Int, factor2:Int, factor3:Int) -> Int{
        return factor1 * factor2 * factor3
    }

}

Here there are two different methods, with different names, multiply(factor2) and multiply(factor2 factor3).

This rule only apply to methods, if you declare this like a functions outside of a class, then the function call don't require parameter name.