Programming

Functions

A function can take zero or more arguments.

In this example, add takes two parameters of type int.

Notice that the type comes after the variable name.

package main

import "fmt"

func add(x int, y int) int {
  return x + y
}

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

When two or more consecutive named function parameters share a type, you can omit the type from all but the last.

In this example, we shortened

x int, y int

to

x, y int

package main

import "fmt"

func add(x, y int) int {
  return x + y
}

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

Multiple results

A function can return any number of results.

The swap function returns two strings.

package main

import "fmt"

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

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

Named return values

Go’s return values may be named. If so, they are treated as variables defined at the top of the function.

These names should be used to document the meaning of the return values.

A return statement without arguments returns the named return values. This is known as a “naked” return.

Naked return statements should be used only in short functions, as with the example shown here. They can harm readability in longer functions.

package main

import "fmt"

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

func main() {
  fmt.Println(split(17))
}