diff --git a/Main.cpp b/Main.cpp
index 297d6ca..fb46dea 100644
--- a/Main.cpp
+++ b/Main.cpp
@@ -34,7 +34,7 @@ int main() {
     //==================================================
     // TEST INSERT AFTER
     P = findElm(L, 6);
-    insertLast(L, allocate(5));
+    insertLast(L, P, allocate(5));
     printInfo(L);
     cout<<"output should be: 8, 3, 6, 5, 4, 2,"<<endl;
 
diff --git a/list.cpp b/list.cpp
index f61d73d..9672bac 100644
--- a/list.cpp
+++ b/list.cpp
@@ -6,8 +6,8 @@ void createList(List &L) {
     */
     //-------------your code here-------------
     cout<<"your code here"<<endl;
-
-
+    
+    first(L) = NULL;
     //----------------------------------------
 }
 
@@ -20,7 +20,9 @@ address allocate(infotype x) {
     //-------------your code here-------------
     cout<<"your code here"<<endl;
 
-
+    P = new elmlist;
+    info(P) = x;
+    next(P) = NULL;
     //----------------------------------------
     return P;
 }
@@ -32,7 +34,7 @@ void deallocate(address &P) {
     //-------------your code here-------------
     cout<<"your code here"<<endl;
 
-
+    delete(P);
     //----------------------------------------
 }
 
@@ -44,8 +46,8 @@ void insertFirst(List &L, address P) {
     //-------------your code here-------------
     cout<<"your code here"<<endl;
 
-
-
+    next(P) = first(L);
+    first(L) = P;
     //----------------------------------------
 }
 
@@ -57,7 +59,12 @@ void insertLast(List &L, address P) {
     //-------------your code here-------------
     cout<<"your code here"<<endl;
 
-
+    address Q;
+    Q = first(L);
+    while(next(Q)!=NULL){
+        Q = next(Q);
+    }
+    next(Q)= P;
     //----------------------------------------
 }
 
@@ -72,7 +79,11 @@ address findElm(List L, infotype x) {
     //-------------your code here-------------
     cout<<"your code here"<<endl;
 
-
+    P = first(L);
+    
+    while ((P != NULL ) && (info(P)!= x)){
+    P = next(P);
+    }
     //----------------------------------------
     return P;
 }
@@ -85,8 +96,11 @@ void deleteFirst(List &L, address &P) {
     //-------------your code here-------------
     cout<<"your code here"<<endl;
 
-
-
+    if (first(L) != NULL){
+        P = first(L);
+        first(L) = next(P);
+        next(P) = NULL;
+    }
     //----------------------------------------
 }
 
@@ -99,7 +113,17 @@ void deleteLast(List &L, address &P) {
     cout<<"your code here"<<endl;
 
 
-
+        address Q;
+    Q = first(L);
+    if (next(Q) == NULL){
+       deleteFirst(L,P);
+    } else {
+        while (next(next(Q))!= NULL ){
+            Q = next(Q);
+        }
+        P = next(Q);
+        next(Q) = NULL;
+    }
     //----------------------------------------
 }
 
@@ -111,7 +135,12 @@ void printInfo(List L) {
     //-------------your code here-------------
     cout<<"your code here"<<endl;
 
-
+    address P;
+    P = first(L);
+    while(P != NULL){
+        cout<<info(P)<<", ";
+        P = next(P);
+    }
     //----------------------------------------
     cout<<endl;
 }
@@ -125,7 +154,9 @@ void insertAfter(List &L, address Prec, address P) {
     */
     //-------------your code here-------------
     cout<<"your code here"<<endl;
-
+    
+    next(P) = next(Prec);
+    next(Prec) = P;
     //----------------------------------------
 
 }
@@ -138,7 +169,9 @@ void deleteAfter(List &L, address Prec, address &P) {
     //-------------your code here-------------
     cout<<"your code here"<<endl;
 
-
+    P = next(Prec);
+    next(Prec)=next(P);
+    next(P)=NULL;
     //----------------------------------------
 }
 
diff --git a/list.h b/list.h
index d021225..5e8af3b 100644
--- a/list.h
+++ b/list.h
@@ -30,14 +30,14 @@ typedef struct elmlist *address;
 
 struct elmlist{
     //------------- your code here -----------
-
-
+     infotype info;
+    address next;
     //----------------------------------------
 };
 
 struct List{
     //------------- your code here -----------
-
+    address first;
     //----------------------------------------
 };
 
diff --git a/operation.cpp b/operation.cpp
index 0a0e067..3bfd551 100644
--- a/operation.cpp
+++ b/operation.cpp
@@ -14,7 +14,22 @@ void insert_sorted(List &L, infotype x) {
 
     //-------------your code here-------------
     cout<<"your code here"<<endl;
-
-
+    address Q,P;
+    if ((first(L) == NULL) || (x < info(first(L)))) {
+        P = allocate(x);
+        insertFirst(L,P);
+    } else if (findElm(L,x)==NULL){
+        Q = first(L);
+        while ((next(Q)!= NULL) && (x > info(next(Q)))){
+            Q = next(Q);
+            if (next(Q) == NULL){
+                P = allocate(x);
+                insertLast(L,P);
+            }else if (info(P)!=info(Q)){
+                P = allocate(x);
+                insertAfter(L,Q,P);
+                }
+            }
+        }
     //----------------------------------------
 }