Example about Guard Statement

OptinalsBindingVsGuard.swift

let name : String? = "Swift"
let nickName : String? = nil

// Example: Optional binding
// Note: underscore "_" using to ignore name of parameter when call function
// Example calling function below
func sayHiWithOptionalBinding(_ name: String?) {
    // Using optional binding to check if object is NOT nil
    if let checkName = name {
        // If not nil, do some logic...
        print("Hi \(checkName)")
        
        // If logic of case object not nil too longgggggg
        // When will you meet "else" case?
        
    } else {
        // If nil, print error or something...
        print("Nobody Here")
    }
}

// Example: Guard Statement
// Note: this is sample of not using underscore too :v
func sayHiWithGuard(name: String?) {
    // Check if object is nil then do logic of nil case first
    guard let checkName = name else {
        // Guard statement using when we need to focus case: object is nil first
        // Or do logic when the condition is not satisfied...
        print("Nobody Here with Guard")
        return
    }
    
    // If object not nil, then do logic
    print("Hello \(checkName)")
}

// function sayHiWithOptionalBinding have underscore parameter,
// then do NOT need a word in front of argument
sayHiWithOptionalBinding(name)
sayHiWithOptionalBinding(nickName)

// function sayHiWithGuard NOT have underscore parameter,
// then do need a word in front of argument
sayHiWithGuard(name: name)
sayHiWithGuard(name: nickName)