Functions

In this chapter, we will look at the basics of function declaration in Swift, and we'll leave the more advanced features until Chapter 5, Advanced Swift.

To define a function in Swift, we use the following syntax:

func functionName(argument: argumentType) -> returnType 
{ 
    // code 
} 

We can define a function that takes no arguments and returns no value as follows:

func printDate() 
{ 
    print(Date()) 
} 

Note that it is not necessary to declare a Void return value, though we may do so if we choose.

We would call that function as follows:

printDate() 

Arguments to the function are supplied in the parentheses following the function name, in the form argName: argType; if there are more than one, they are separated by commas:

func printPoint(x: Int, y:Int) 
{ 
    print(x, y) 
} 

We would call that function as follows:

printPoint(x: 11, y: 59) 

The argument value(s) must be preceded by the argument name(s), as can be seen previously.

Note

Here we go again: This is new in Swift 3, so you...