In Swift, you can declare a method or function using the func keyword followed by the function name, parameter list (if any) in parentheses, and the return type (if any). Here are a few examples:
1. A simple function that takes no parameters and returns a string:
func sayHello() -> String {
return "Hello"
}
2. A function that takes two integers and returns their sum:
func addNumbers(_ a: Int, _ b: Int) -> Int {
return a + b
}
In the above example, the underscore before each parameter name indicates that they are unnamed parameters.
3. A function that takes an array of strings and returns a concatenated string:
func joinStrings(_ strings: [String]) -> String {
return strings.joined(separator: " ")
}
Here, the function takes an array of strings as a parameter, and returns a single string that is a concatenation of all the strings in the array, separated by a space.
4. A method that belongs to a class:
class Person {
var name: String
init(name: String) {
self.name = name
}
func introduce() {
print("Hi, my name is \(name)")
}
}
let john = Person(name: "John")
john.introduce() // Output: "Hi, my name is John"
In the above example, the Person class has a method called introduce which doesn't take any parameter but prints out a message including the name of the Person object.