Inout Update - Swift Programming

An inout parameter makes mutation explicit at the call site.

Pass a value for update

inout_update.swift

func addBonus(to score: inout Int, bonus: Int) {
    score += bonus
}

let bonus = 
var score = 10
addBonus(to: &score, bonus: bonus)
let message = "score=\(score)"

print(message)

func addBonus(to score: inout Int, bonus: Int) {
    score += bonus
}

let bonus = 
var score = 10
addBonus(to: &score, bonus: bonus)
let message = "score=\(score)"

print(message)

func addBonus(to score: inout Int, bonus: Int) {
    score += bonus
}

let bonus = 
var score = 10
addBonus(to: &score, bonus: bonus)
let message = "score=\(score)"

print(message)

inout The `&` marker shows where a function is allowed to update the caller's variable.