updated singly circular linked list

SinglyCircularLinkedList.go

@@ -175,6 +175,25 @@ func main() {
     fmt.Println("Initial condition:")
     s.PrintToRight()
 
+    fmt.Printf("\nInsert \"hello\" as head and set old head as head's prev\n")
+    s.InsertPrev(&Node{"hello", nil})
+    s.PrintToRight()
+    fmt.Printf("\nInsert \"world\" as head and set old head as head's prev\n")
+    s.InsertPrev(&Node{"world", nil})
+    s.PrintToRight()
+    fmt.Printf("\nInsert 3.14 as head and set old head as head's next\n")
+    s.InsertNext(&Node{3.14, nil})
+    s.PrintToRight()
+    fmt.Printf("\nDelete head and set head's prev as new head\n")
+    s.DeletePrev()
+    s.PrintToRight()
+    fmt.Printf("\nDelete head and set head's next as new head\n")
+    s.DeleteNext()
+    s.PrintToRight()
+    fmt.Printf("\nDelete head and set head's next as new head\n")
+    s.DeleteNext()
+    s.PrintToRight()
+
     for i := 1; i <= 3; i++ {
         fmt.Printf("\nInsert %d as head and set old head as head's next\n",i)
         s.InsertNext(&Node{i, nil})