Golang basics: function declaration

To document my learning in Golang, here are some basic syntax rules for Golang functions.

• A function can take zero or more arguments
• The types comes after the variable name

func add(x, y int) int {
return x, y
}
// func add(x int, y int) int is also fine

func main() {
	fmt.Println(add(42, 13))
}
// 55

Expression

func main() {	 
    add := func(x, y int) int {
    return x + y
  }
	fmt.Println(add(5,6))
}
// 11

Multiple results

func swap(x, y string) (string, string) {
	return y, x
}

func main() {
	a, b := swap("hello", "world")
	fmt.Println(a, b)
}
// world hello

• To do swap, we can also directly use a, b = b, a.

Named return values (Naked return)

• A return statement without arguments returns the named return values. 
• Encouraged be used only in short functions because it might harm readability in longer functions

func split(sum int) (x, y int) {
	x = sum * 4 / 9
	y = sum - x
	return
}

func main() {
	fmt.Println(split(17))
}
// 7 10
// 

Return a function

func foo() func() int {
  return func() int {
    return 100
  }
}
// the returned function will return an int

func main() {
  bar := foo()            // bar will be a function
  fmt.Printf("%T\n", bar) // print the type: func() int
  fmt.Println(bar())      // 100
}

Reference

fmt package - fmt - Go Packages

Go

A Tour of Go

A Tour of Go

[Golang] function & method 函式與方法 | PJCHENder 未整理筆記

函式宣告

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