Functions

func sayHello() {
    // Hello World!
}
sayHello() // Hello World!

func sum(x int, y int) int {
    return x + y
}
sum(3, 7) // 10

func doubleAndTriple(x int) (double, triple int) {
    double = x * 2
    triple = x * 3
    return
}
d, t := doubleAndTriple(5)
// d = 10
// t = 15
 
 
// Skipping one of the returned values
_, t := doubleAndTriple(3)
// t = 9

var aux = 0
 
func switchValuesAndDouble(x, y int) {
    aux = x
    defer aux = 0 // cleaning variable to post use
    x = y * 2
    y = aux * 2
}
 
a, b = 2, 5
switchValuesAndDouble(2, 5)
 
// a = 10
// b = 4
// aux = 0

func calc(fn func(int, int) int) int {
    return fn(2, 6)
}
 
func sum(x, y int) int {
    return x + y
}
 
func mult(x, y int) int {
    return x * y
}
 
calc(sum) // 8
calc(mult) // 12
calc(
    func(x, y int) int {
		return x / y
    }
) // 3

func calc() func(int) int {
value := 0
return func(x int) int {
value += x
return value
}
}
 
calculator := calc()
calculator(3) // 3
calculator(45) // 48
calculator(12) // 60