Using a pointer to array

Question

I\'m having a little play with google\'s Go language, and I\'ve run into something which is fairly basic in C but doesn\'t seem to be covered in the documentation I\'ve seen

Answer 1

Types with empty [], such as []int are actually slices, not arrays. In Go, the size of an array is part of the type, so to actually have an array you would need to have something like [16]int, and the pointer to that would be *[16]int. So, what you are actually doing already is using slices, and the pointer to a slice, *[]int, is unnecessary as slices are already passed by reference.

Also remember that you can easily pass a slice referring to the entire array with &array (as long as the element type of the slice matches that of the array). (Not anymore.)

Example:

package main
import "fmt"

func sumPointerToArray(a *[8]int) (sum int) {
    for _, value := range *a { sum += value }
    return
}
func sumSlice (a []int) (sum int) {
    for _, value := range a { sum += value }
    return
}
func main() {
    array := [...]int{ 1, 2, 3, 4, 5, 6, 7, 8 }
    slice := []int{ 1, 2, 3, 4 }
    fmt.Printf("sum arrray via pointer: %d\n", sumPointerToArray(&array))
    fmt.Printf("sum slice: %d\n", sumSlice(slice))
    slice = array[0:]
    fmt.Printf("sum array as slice: %d\n", sumSlice(slice))
}

Edit: Updated to reflect changes in Go since this was first posted.