Day 5

100 Days of SwiftUI

I learned two new things about functions today during Day 5 of 100 Days of SwiftUI.

Variadic functions allow for mutliple parameters to be used in a function without predetermining the number of parameters. For example print() can take any number of parameters and will print all of the inputs.

I also learned about inout parameters. Declaring a function parameter as inout makes the functions capable of modifying the passed in parameter outside the scope of the function. We write the functions as follows:

func doubleInPlace(number: inout Int) {
    number *= 2

To use this function when calling we need to explicitly indicate that we know the parameter is changing by prepending an ‘&’ infront of the parameter. To use this we need to declare a variable not a constant.

var num = 10 
doubleInPlace(number: &num)

I believe that it would better to return the value but I will look for a good reason to use this type of syntax.