diff --git a/case_study/advanced/m b/case_study/advanced/m
deleted file mode 100755
index 4ff1311..0000000
Binary files a/case_study/advanced/m and /dev/null differ
diff --git a/iterator/introduce_iterator.cpp b/iterator/introduce_iterator.cpp
new file mode 100644
index 0000000..fb804dc
--- /dev/null
+++ b/iterator/introduce_iterator.cpp
@@ -0,0 +1,47 @@
+#include <iostream>
+#include <vector>
+#include <list>
+/**
+ * @brief ITERATOR
+ * iterator adalah pointer pintar yang mununjuk element dalam suatu container
+ * iterator begin selalu mununjuk element pertama
+ * iterator end selalu mununjuk element terakhir
+ */
+
+void _iterator(){
+    /*
+    iterator vector di sebut bidirectional iterator karena dapat bergerak maju dan mundur
+    */
+    std::vector<int>v = {1,2,3,4,5};
+    std::vector<int>::iterator it; //deklarasi iterator
+    //akan mencetak element pada array v
+    for(it = v.begin();it != v.end();++it){
+        std::cout << *it << "  ";
+    }
+    std::cout << std::endl;
+    //akan mencetak alamat memory
+    for(it = v.begin();it != v.end();it += 2){
+        std::cout << &it << "  ";
+    }
+    /*
+    it selalu  menunjuk alamat memory dari vector v
+    *it arti nya melakukan deferencing terhadap alamat memory tersebut
+    */
+   std::list<int>l= {1,2,3,4,5,6,7};
+   std::list<int>::iterator lst;
+   std::cout << std::endl;
+   /**
+    * list hanya dapat bergerak satu arah karena memakai linked list 
+    * linked list menyimpan data secara tidak beraturan,semua data tersebar di heap
+    * tp masing node punya alamat ke node berikut nya.
+    * berbeda dengan array yg berurutan di heap atau di stack
+    */  
+    for(lst = l.begin();lst != l.end();lst++){
+        std::cout << *lst << " ";
+    }
+}
+int main(){
+    _iterator();
+    //std::cin.get();
+    return 0;
+}
\ No newline at end of file
diff --git a/src/m b/src/m
deleted file mode 100755
index a155216..0000000
Binary files a/src/m and /dev/null differ
diff --git a/src/stack_linked_list.cpp b/src/stack_linked_list.cpp
index f0c5151..ca99012 100644
--- a/src/stack_linked_list.cpp
+++ b/src/stack_linked_list.cpp
@@ -10,6 +10,7 @@
  *
  * @version 2.0
  */
+
 #include <iostream>
 #include <stdexcept>
 template <typename type>
@@ -68,6 +69,15 @@ class Stack{
         ~Stack()noexcept{
             clear();
         }
+        void swap(Stack& others){
+            //swap head
+            Node* tempHead = head;
+            head = others.head;
+            //swap size
+            int tempSize = size;
+            size = others.size;
+            others.size = tempSize;
+        }
     public://abstraksi getter
         int is_size()const noexcept{
             return this->size;
@@ -162,6 +172,16 @@ int main(){
     stack3 = stack1;
     std::cout << "copy assignment" << std::endl;
     stack3.print_detail();
+    Stack<int> stack4;
+    stack4.push(10);
+    stack4.push(20);
+    stack4.push(30);
+    stack4.push(40);
+    std::cout << "sebelum swap" << std::endl;
+    stack4.print_detail();
+    stack4.swap(stack1);
+    std::cout << "sesudah swap" << std::endl;
+    stack4.print_detail();
     std::cin.get();
     return 0;
 } 
\ No newline at end of file