diff --git a/main.cpp b/main.cpp
new file mode 100644
index 0000000..8827aa1
--- /dev/null
+++ b/main.cpp
@@ -0,0 +1,388 @@
+#include <iostream>
+#include <fstream>
+#include <string>
+
+
+using namespace std;
+
+struct contacts *FindNode(string);
+
+struct contacts {
+    string name;
+    string phone;
+    string fax;
+    string job;
+    string email;
+    string address;
+    string qq;
+    string folder;
+    struct contacts *next;
+};
+// create head node
+contacts *head = NULL;
+
+
+void PrintMenu(void) {
+    cout << "*********************************************************" << endl;
+    cout << "1.Add contacts" << endl;
+    cout << "2.Find contacts" << endl;
+    cout << "3.Edit" << endl;
+    cout << "4.Delete" << endl;
+    cout << "5.List all" << endl;
+    cout << "6.Filter and print" << endl;
+    cout << "8.Load data.csv" << endl;
+    cout << "9.Save to data.csv" << endl;
+    cout << "0.Exit" << endl;
+    cout << "*********************************************************" << endl;
+
+}
+
+
+void DeleteAll(void) {
+    contacts *p = head;
+    while (p != NULL) {
+        head = p->next;
+        delete p;
+        p = head;
+    }
+}
+
+void
+AddNode(string name, string phone, string fax, string job, string email, string address, string qq, string folder) {
+    contacts *p = new contacts;
+    p->name = name;
+    p->phone = phone;
+    p->fax = fax;
+    p->job = job;
+    p->email = email;
+    p->address = address;
+    p->qq = qq;
+    p->folder = folder;
+    p->next = NULL;
+    if (head == NULL) {
+        head = p;
+    } else {
+        contacts *q = head;
+        while (q->next != NULL) {
+            q = q->next;
+        }
+        q->next = p;
+    }
+}
+
+
+void AddContacts(void) {
+    while (1) {
+        //input a name,check if the name is already in the linked list
+        //if yes,ask user to input another name
+        string input_name;
+        cout << "input a name:";
+        cin >> input_name;
+        //get the node address of the name
+        contacts *p = NULL;
+        p = FindNode(input_name);
+        //check if the name is already in the linked list
+        // if not,create a new node and add it to the linked list
+        if (p == NULL) {
+            //input other information
+            string input_phone;
+            string input_fax;
+            string input_job;
+            string input_email;
+            string input_address;
+            string input_qq;
+            string input_folder;
+            cout << "input phone:";
+            cin >> input_phone;
+            cout << "input fax:";
+            cin >> input_fax;
+            cout << "input job:";
+            cin >> input_job;
+            cout << "input email:";
+            cin >> input_email;
+            cout << "input address:";
+            cin >> input_address;
+            cout << "input qq:";
+            cin >> input_qq;
+            cout << "input folder:";
+            cin >> input_folder;
+            //add the node to the linked list
+            AddNode(input_name, input_phone, input_fax, input_job, input_email, input_address, input_qq, input_folder);
+            cout << "add successfully" << endl;
+
+        } else {
+            cout << "the name is already in the linked list" << endl;
+            cout << "please input another name" << endl;
+        }
+//ask user continue or stop
+        char input_char;
+        cout << "continue?(y/n)" << endl;
+        cin >> input_char;
+        if (input_char == 'n') {
+            break;
+        }
+    }
+}
+
+
+void FindContacts(void) {
+//find the node by name
+//output data
+    struct contacts *p;
+    p = head;
+    cout << "input name:";
+    string name;
+    cin >> name;
+    while (p != NULL) {
+        if (p->name == name) {
+            cout << "name:" << p->name << endl;
+            cout << "phone:" << p->phone << endl;
+            cout << "fax:" << p->fax << endl;
+            cout << "job:" << p->job << endl;
+            cout << "email:" << p->email << endl;
+            cout << "address:" << p->address << endl;
+            cout << "qq:" << p->qq << endl;
+            cout << "folder:" << p->folder << endl;
+            break;
+        }
+        p = p->next;
+    }
+}
+
+struct contacts *FindNode(string name) {
+//find the node by name
+// return NULL if not found
+    struct contacts *p;
+    p = head;
+    while (p != NULL) {
+        if (p->name == name) {
+            return p;
+        }
+        p = p->next;
+    }
+    return NULL;
+}
+
+/*
+struct contacts *FindNodeByFolders(string folder){
+    struct contacts *p;
+    p = head;
+    while(p != NULL){
+        if(p->folder == folder){
+            return p;
+        }
+        p = p->next;
+    }
+    return NULL;
+}
+*/
+void EditContacts(void) {
+//find the node by name
+//input name
+    string name;
+    cout << "input the name you want to edit:";
+    cin >> name;
+// get node address by name
+    struct contacts *p;
+    p = FindNode(name);
+    if (p == NULL) {
+        cout << "not found" << endl;
+        return;
+    }
+//if it was found , then input new data
+    cout << "input new name:";
+    cin >> p->name;
+    cout << "input new phone:";
+    cin >> p->phone;
+    cout << "input new fax:";
+    cin >> p->fax;
+    cout << "input new job:";
+    cin >> p->job;
+    cout << "input new email:";
+    cin >> p->email;
+    cout << "input new address:";
+    cin >> p->address;
+    cout << "input new qq:";
+    cin >> p->qq;
+    cout << "input new folder:";
+    cin >> p->folder;
+// Edit finished
+    cout << "Edit finished" << endl;
+
+}
+
+void DeleteContacts(void) {
+    while (true) {
+//find the node by name
+//input name
+        string name;
+        cout << "input the name you want to delete:";
+        cin >> name;
+// get node address by name
+        struct contacts *p;
+        p = FindNode(name);
+// check if the name is already in the linked list
+// if not ,print error message
+        if (p == NULL) {
+            cout << "not found" << endl;
+
+        }
+// if it was found , then delete it
+        else {
+            if (p == head) {
+                head = head->next;
+            } else {
+                struct contacts *q = head;
+                while (q->next != p) {
+                    q = q->next;
+                }
+                q->next = p->next;
+            }
+            delete p;
+            cout << "delete successfully" << endl;
+        }
+//ask user continue or stop
+        char input_char;
+        cout << "continue?(y/n)" << endl;
+        cin >> input_char;
+        if (input_char == 'n') {
+            break;
+        }
+    }
+}
+
+void ListAllContacts(void) {
+    //print all the contacts as table
+    struct contacts *p;
+    p = head;
+    cout << "name" << "\t" << "phone" << "\t" << "fax" << "\t" << "job" << "\t" << "email" << "\t" << "address" << "\t"
+         << "qq" << "\t" << "folder" << endl;
+    while (p != NULL) {
+        cout << p->name << "\t" << p->phone << "\t" << p->fax << "\t" << p->job << "\t" << p->email << "\t"
+             << p->address << "\t" << p->qq << "\t" << p->folder << endl;
+        p = p->next;
+    }
+
+}
+
+void Filter(void) {
+    //filter by folder
+    string folder;
+    cout << "input the folder you want to filter:";
+    cin >> folder;
+    // print the filter result as table
+    struct contacts *p;
+    p = head;
+    cout << "name" << "\t" << "phone" << "\t" << "fax" << "\t" << "job" << "\t" << "email" << "\t" << "address" << "\t"
+         << "qq" << "\t" << "folder" << endl;
+    while (p != NULL) {
+        if (p->folder == folder) {
+            cout << p->name << "\t" << p->phone << "\t" << p->fax << "\t" << p->job << "\t" << p->email << "\t"
+                 << p->address << "\t" << p->qq << "\t" << p->folder << endl;
+        }
+        p = p->next;
+    }
+
+}
+
+// load data from csv file
+void OpenFile() {
+    DeleteAll();
+    // load data from csv file to linked list
+    ifstream fin;
+    fin.open("contacts.csv");
+    if (!fin) {
+        cout << "open file error" << endl;
+        return;
+    }
+    string name, phone, fax, job, email, address, qq, folder;
+    while (!fin.eof()) {
+        getline(fin, name, ',');
+        getline(fin, phone, ',');
+        getline(fin, fax, ',');
+        getline(fin, job, ',');
+        getline(fin, email, ',');
+        getline(fin, address, ',');
+        getline(fin, qq, ',');
+        getline(fin, folder);
+        if (name == "") {
+            break;
+        }
+        AddNode(name, phone, fax, job, email, address, qq, folder);
+    }
+    fin.close();
+}
+
+
+// save the data to file as csv
+void SaveToFile(void) {
+    ofstream outfile;
+    outfile.open("contacts.csv");
+    struct contacts *p;
+    p = head;
+    while (p != NULL) {
+        outfile << p->name << "," << p->phone << "," << p->fax << "," << p->job << "," << p->email << "," << p->address
+                << "," << p->qq << "," << p->folder << endl;
+        p = p->next;
+    }
+    outfile.close();
+}
+
+
+int main() {
+    while (1) {
+        system("pause");
+        system("cls");
+        // print menu
+        PrintMenu();
+        // read a choice
+        int choice;
+        //1.Add a new contact
+        //2.Find a contact
+        //3.Edit a contact
+        //4.Delete a contact
+        //5.List all contacts
+        //6.Filter by folder
+        //8.Load data from file
+        //9.Save data to file
+        //10.Exit
+
+
+        cout << "please input your choice:";
+        cin >> choice;
+        switch (choice) {
+            case 1:
+                AddContacts();
+                break;
+            case 2:
+                FindContacts();
+                break;
+            case 3:
+                EditContacts();
+                break;
+            case 4:
+                DeleteContacts();
+                break;
+            case 5:
+                ListAllContacts();
+                break;
+            case 6:
+                Filter();
+                break;
+            case 8:
+                OpenFile();
+                break;
+            case 9:
+                SaveToFile();
+                break;
+            case 0:
+                exit(0);
+            default:
+                cout << "input error" << endl;
+                break;
+        }
+    }
+}
+
+
+