Create functionPart2.swift

functionPart2.swift

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+// declaring a function
+
+func functionName(parameters)-> returnType {
+  // function body
+}
+
+functionName(arguments) // calling a function
+
+func - keyword used to declare a function
+functionName - any name given to a function
+parameters - any value passed to function
+returnType - specifies the type of value returned by the function
+
+// sum of two numbers
+
+func addTwo(num1 : Int, num2: Int)-> Int{
+  return num1 + num2
+}
+
+addTwo(num1 : 2, num2 : 2)
+
+// parameters
+// default parameters
+
+func addTwo(num1 : Int = 1, num2: Int = 2)-> Int{
+  return num1 + num2
+}
+
+addTwo() // 3 - if we don't give any arguments, it takes the default
+addTwo(num1: 2) // 4 - if we pass any arguments, it takes the given arguments
+addTwo(num1: 2, num2: 3) // 5
+
+// Function With Argument Label - we can use the argument labels to define a function in an expressive and sentence-like manner
+
+func addTwo(of num1: Int, and num2: Int)-> Int{
+    return num1 + num2
+}
+
+addTwo(of: 4, and: 4)
+
+// Omit Argument Labels - If we use _ before the parameter name, then we can call the function without an argument label or parameter name
+
+func addTwo(_ num1: Int,_ num2: Int)-> Int{
+    return num1 + num2
+}
+
+addTwo(4, 4)
+
+// Function with variadic parameters - In some cases we don't know how many parameters we'll be passing, in that case, we can use ... after the parameter's type.
+
+func guests(names: String...){
+    for name in names{
+        print("hello \(name)")
+    }
+}
+
+guests(names: "Alice", "Beth", "Cathy") 
+"""
+hello Alice
+hello Beth
+hello Cathy
+"""
+
+guests(names: "Alexa", "Siri")
+"""
+hello Alexa
+hello Siri
+"""
+
+// Function With inout Parameters - When we define a function parameter, the function parameter cannot be modified inside the function body
+
+func changeName(name: String){
+    if name == "Alice"{
+        name = "Beth" // Error -  cannot assign value to name; it's a let constant
+}
+
+changeName(name: "Alice") 
+
+// using inout parameters 
+
+func changeName(name: inout String){
+  if name == "Alice"{
+      name = "Beth"
+  }
+}
+var username = "Alice"
+print("before: ", username ) // before:  Alice
+changeName(name: &username) // While calling a function with inout parameter, we must use the ampersand(&) sign before a variable name passed as an argument.
+print("after: ", username ) // after:  Beth
+
+// Function Return Values
+
+func flavours(flavour1: String, flavour2: String)-> String {
+  return "my flavours \(flavour1) \(flavour2) are great"
+}
+
+flavours(flavour1: "Chocolate", flavour2: "Vanilla")
+
+// Multiple return values
+
+func compute(number: Int)-> (Int, Int, Int){
+    var sqaure = number * number
+    var cube = number * number * number
+    return [sqaure, cube, number]
+}
+
+var result = compute(number: 5) // The returned values are stored in result. Here, result is a tuple that stores multiple values. 
+print(result.0) // To access individual values from a tuple, we use the index number. That's why result.0 returns 5, result.1 returns 25, and results.2 returns 125
+print(result.1)
+print(result.2)
+
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