content: expand discussion of methods

Fixes golang/go#13818

Change-Id: I22817c0c3bfa3d7e5a769f239a2521c293112a43
Reviewed-on: https://go-review.googlesource.com/18246
Reviewed-by: Rob Pike <r@golang.org>

1 files changed, 27 insertions, 0 deletions

diff --git a/content/methods/methods-pointers-explained.go b/content/methods/methods-pointers-explained.go
new file mode 100644
index 0000000..db9107a
--- /dev/null
+++ b/content/methods/methods-pointers-explained.go
@@ -0,0 +1,27 @@
+// +build OMIT
+
+package main
+
+import (
+	"fmt"
+	"math"
+)
+
+type Vertex struct {
+	X, Y float64
+}
+
+func Abs(v Vertex) float64 {
+	return math.Sqrt(v.X*v.X + v.Y*v.Y)
+}
+
+func Scale(v *Vertex, f float64) {
+	v.X = v.X * f
+	v.Y = v.Y * f
+}
+
+func main() {
+	v := Vertex{3, 4}
+	Scale(&v, 10)
+	fmt.Println(Abs(v))
+}