Magic Boxes (func)

Grouping repeated code and giving it a name is called a function. In Go, we use the word func.

Create a function

func sayHello() {
    fmt.Println("Hi!")
}

func main() {
    sayHello() // use the box
}

Ingredients and results

Go is strict: you must specify the type of each input and output.

func add(a int, b int) int {
    return a + b
}

func main() {
    result := add(10, 20)
    fmt.Println(result)
}

Translation:

Define a magic box called add:
    (inputs are numbers a and b)
    (output is a number)
    {
        return a + b
    }

Go’s special power: multiple returns

Go’s magic box can return multiple results at once.

func swap(a string, b string) (string, string) {
    return b, a
}

Put in two ingredients, and two swapped results pop out.

That clarity and power is one of Go’s biggest strengths.