Golang GoCourseDay1.pdf slide 53

Function_literals_are_closures.go

package main

import "fmt"

func adder() (func(int) int) { //declare function adder() with the function literal func(int) as a parameter of type int
	var x int
	return func(delta int) int {
		x += delta
		return x
	}
}

func main() {
	var f = adder()
	fmt.Print(f(1))
	fmt.Print(f(1))
}