Functions and Closures

里面第一个例子更新了。

Use func to declare a function. Call a function by following its name with a list of arguments in parentheses. Use -> to separate the parameter names and types from the function’s return type.

func greet(person: String, day: String) -> String {
return "Hello \(person), today is \(day)."
}
greet(person: "Bob", day: "Tuesday")

By default, functions use their parameter names as labels for their arguments. Write a custom argument label before the parameter name, or write _ to use no argument label.

func greet(_ person: String, on day: String) -> String {
return "Hello \(person), today is \(day)."
}
greet("John", on: "Wednesday")