update book code

eBook/examples/chapter_11/emptyint_switch.go

@@ -0,0 +1,32 @@
+package main
+
+import "fmt"
+
+type specialString string
+
+var whatIsThis specialString = "hello"
+
+func TypeSwitch() {
+	testFunc := func(any interface{}) {
+		switch v := any.(type) {
+		case bool:
+			fmt.Printf("any %v is a bool type", v)
+		case int:
+			fmt.Printf("any %v is an int type", v)
+		case float32:
+			fmt.Printf("any %v is a float32 type", v)
+		case string:
+			fmt.Printf("any %v is a string type", v)
+		case specialString:
+			fmt.Printf("any %v is a special String!", v)
+		default:
+			fmt.Println("unknown type!")
+		}
+	}
+	testFunc(whatIsThis)
+}
+
+func main() {
+	TypeSwitch()
+}
+// Output:  any hello is a special String!