go.blog/slices: fix bug in Append

The code didn't work but the blog runs the previous simple version, which does,
so when you hit Run it looks like it's working.
It only had two bugs (so far).

Thanks to shelah.kell@gmail.com for noticing.

R=adg
CC=golang-dev
https://golang.org/cl/14036043

1 files changed, 3 insertions, 3 deletions

diff --git a/content/slices/prog140.go b/content/slices/prog140.go
index 306d6f2..ab04d97 100644
--- a/content/slices/prog140.go
+++ b/content/slices/prog140.go
@@ -11,7 +11,8 @@ import (
 // Append appends the elements to the slice.
 // Efficient version.
 func Append(slice []int, elements ...int) []int {
-	total := len(slice) + len(items)
+	n := len(slice)
+	total := len(slice) + len(elements)
 	if total > cap(slice) {
 		// Reallocate. Grow to 1.5 times the new size, so we can still grow.
 		newSize := total*3/2 + 1
@@ -19,9 +20,8 @@ func Append(slice []int, elements ...int) []int {
 		copy(newSlice, slice)
 		slice = newSlice
 	}
-	n := len(slice)
 	slice = slice[:total]
-	copy(slice[:n], elements)
+	copy(slice[n:], elements)
 	return slice
 }