diff --git a/list.cpp b/list.cpp
index 847a957..751c734 100644
--- a/list.cpp
+++ b/list.cpp
@@ -5,7 +5,7 @@ void createList(List &L) {
     * FS : first(L) diset Nil
     */
     //------------- YOUR CODE HERE -------------
-
+     first(L) == NULL;
     //----------------------------------------
 }
 
@@ -17,7 +17,10 @@ address allocate(infotype x) {
 
     address P = NULL;
     //------------- YOUR CODE HERE -------------
-
+    P = new elmlist;
+        info(P) = x;
+        next(P) = NULL;
+        prev(P) = NULL;
     //----------------------------------------
     return P;
 }
@@ -27,7 +30,7 @@ void deallocate(address &P) {
     * FS : menghapus elemen yang ditunjuk oleh P (delete)
     */
     //------------- YOUR CODE HERE -------------
-
+    delete P;
     //----------------------------------------
 }
 
@@ -37,7 +40,20 @@ void insertFirst(List &L, address P) {
     * FS : elemen yang ditunjuk P menjadi elemen pertama pada List L
     */
     //------------- YOUR CODE HERE -------------
-
+    if ( first(L) == NULL )
+    {
+        first(L) = P;
+        next(P) = P;
+        prev(P) = P;
+    }
+    else
+    {
+        next(P) = first(L) ;
+        prev(P) = prev(first(L));
+        next(prev(first(L))) = P;
+        prev(first(L)) = P;
+        first(L) = P;
+    }
     //----------------------------------------
 }
 
@@ -47,7 +63,19 @@ void insertLast(List &L, address P) {
     * FS : elemen yang ditunjuk P menjadi elemen terakhir pada List L
     */
     //------------- YOUR CODE HERE -------------
-
+    address Prec;
+    Prec = first(L);
+    if (first(L) == NULL)
+    {
+        insertFirst(L,P);
+    }
+    else
+    {
+        next(P) = first(L);
+        prev(P) = prev(first(L));
+        next(prev(first(L))) = P;
+        prev(first(L)) = P;
+    }
     //----------------------------------------
 }
 
@@ -60,7 +88,16 @@ address findElmByID(List L, infotype x) {
 
     address P = NULL;
     //------------- YOUR CODE HERE -------------
-
+    P = first(L);
+    do
+    {
+        P = next(P);
+    }
+    while((P != first(L)) && (x.ID != info(P).ID)) ;
+    if ((P == first(L)) && (x.ID != info(P).ID))
+    {
+        return NULL;
+    }
     //----------------------------------------
     return P;
 }
@@ -74,7 +111,16 @@ address findElmByName(List L, infotype x) {
 
     address P = NULL;
     //------------- YOUR CODE HERE -------------
-
+     P = first(L);
+    do
+    {
+        P = next(P);
+    }
+    while((P != first(L)) && (x.name != info(P).name));
+    if (P == first(L) && (x.name != info(P).name))
+    {
+        return NULL;
+    }
     //----------------------------------------
     return P;
 }
@@ -95,7 +141,21 @@ void deleteLast(List &L, address &P) {
     * FS : elemen tarakhir di dalam List L dilepas dan disimpan/ditunjuk oleh P
     */
     //------------- YOUR CODE HERE -------------
-
+    P = first(L);
+    if (next(P) == first(L))
+    {
+        first(L) = NULL;
+        next(P) = NULL;
+        prev(P) = NULL;
+    }
+    else
+    {
+        first(L) = next(first(L));
+        next(prev(P)) = first(L);
+        prev(first(L)) = prev(P);
+        next(P) = NULL;
+        prev(P) = NULL;
+    }
     //----------------------------------------
 }
 
@@ -106,7 +166,10 @@ void insertAfter(List &L, address &Prec, address P) {
     *      ditunjuk pointer Prec
     */
     //------------- YOUR CODE HERE -------------
-
+    prev(next(Prec)) = P;
+    next(P) = next(Prec);
+    next(Prec) = P;
+    prev(P) = Prec;
     //----------------------------------------
 
 }
@@ -117,7 +180,21 @@ void deleteAfter(List &L, address &Prec, address &P) {
     *      dan disimpan/ditunjuk oleh P
     */
     //------------- YOUR CODE HERE -------------
-
+    P = next(Prec);
+    if (next(next(Prec)) == Prec)
+    {
+        next(P) = NULL;
+        prev(P) = NULL;
+        next(Prec) = Prec;
+        prev(Prec) = Prec;
+    }
+    else
+    {
+        next(Prec) = next(P);
+        prev(next(P)) = Prec;
+        next(P) = NULL;
+        prev(P) = NULL;
+    }
     //----------------------------------------
 }