go-tour: add Stringer, Reader discussions and exercises; other tweaks

LGTM=campoy
R=campoy
CC=golang-codereviews
https://golang.org/cl/118170043

1 files changed, 17 insertions, 0 deletions

diff --git a/content/methods/exercise-stringer.go b/content/methods/exercise-stringer.go
new file mode 100644
index 0000000..ef656b4
--- /dev/null
+++ b/content/methods/exercise-stringer.go
@@ -0,0 +1,17 @@
+package main
+
+import "fmt"
+
+type IPAddr [4]byte
+
+// TODO: Add a "String() string" method to IPAddr.
+
+func main() {
+	addrs := map[string]IPAddr{
+		"loopback":  {127, 0, 0, 1},
+		"googleDNS": {8, 8, 8, 8},
+	}
+	for n, a := range addrs {
+		fmt.Printf("%v: %v\n", n, a)
+	}
+}