update

ch07/circular.go

@@ -0,0 +1,26 @@
+type CircularLinkedList struct {
+	tail *Node
+	count int
+}
+
+type Node struct {
+	value int
+	next *Node
+}
+
+func (list *CircularLinkedList) Size() int {
+	return list.count
+}
+
+func (list *CircularLinkedList) IsEmpty() bool {
+	return list.count == 0
+}
+
+func (list * CircularLinkedList) Peek() (int, bool) {
+	if list.IsEmpty() {
+		fmt.Println("EmptyListError")
+		return 0, false
+	}
+	return list.tail.next.value, true
+}
+