Added oct cat example

openclose/main.go

@@ -0,0 +1,29 @@
+package main
+
+import "fmt"
+
+type Cat struct {
+	Name string
+}
+
+func (c Cat) Legs() int {
+	return 4
+}
+
+func (c Cat) PrintLegs() {
+	fmt.Printf("I have %d legs", c.Legs())
+}
+
+type OctCat struct {
+	Cat
+}
+
+func (o OctCat) Legs() int {
+	return 5
+}
+
+func main() {
+	var oct OctCat
+	fmt.Println(oct.Legs())
+	oct.PrintLegs()
+}