diff --git a/lesson_7/data.bin b/lesson_7/data.bin
new file mode 100644
index 0000000..b04bbbe
Binary files /dev/null and b/lesson_7/data.bin differ
diff --git a/lesson_7/exercise_2.hpp b/lesson_7/exercise_2.hpp
new file mode 100644
index 0000000..f79bfef
--- /dev/null
+++ b/lesson_7/exercise_2.hpp
@@ -0,0 +1,53 @@
+/*
+ * exercise_2.hpp
+ *
+ *  Created on: 15 окт. 2021 г.
+ *      Author: alexander
+ */
+
+#pragma once
+
+#include <iostream>
+#include <numeric>
+#include <fstream>
+#include "src-gen/exercise_2.pb.h"
+
+void exercise_1_2()
+{
+    exercise_2::FullName fn;
+    fn.set_name("Alexander");
+    fn.set_surname("Zhirov");
+    fn.set_patronymic("Alexandrovich");
+
+    exercise_2::Student s;
+    *s.mutable_name() = fn;
+    s.add_grades(5);
+    s.add_grades(2);
+    s.add_grades(4);
+    s.add_grades(3);
+    s.add_grades(4);
+    s.add_grades(3);
+    s.add_grades(4);
+    s.add_grades(3);
+    s.set_avg_score(std::accumulate(s.grades().begin(), s.grades().end(), 0) / s.grades().size());
+
+    exercise_2::StudentsGroup sg;
+    *sg.add_students() = s;
+
+    std::ofstream out("student.bin", std::ios_base::binary);
+    sg.SerializeToOstream(&out);
+    out.close();
+
+    exercise_2::StudentsGroup new_sg;
+    std::ifstream in("student.bin", std::ios_base::binary);
+    if (new_sg.ParseFromIstream(&in))
+    {
+        std::cout << new_sg.students(0).name().surname() << std::endl;
+        std::cout << new_sg.students(0).avg_score() << std::endl;
+    }
+    else
+    {
+        std::cout << "Error!" << std::endl;
+    }
+    in.close();
+}
diff --git a/lesson_7/exercise_3.cpp b/lesson_7/exercise_3.cpp
new file mode 100644
index 0000000..bd3f3ca
--- /dev/null
+++ b/lesson_7/exercise_3.cpp
@@ -0,0 +1,38 @@
+/*
+ * exercise_3.cpp
+ *
+ *  Created on: 15 окт. 2021 г.
+ *      Author: alexander
+ */
+
+#include "exercise_3.hpp"
+#include <numeric>
+
+void exercise_3()
+{
+    exercise_2::FullName fn;
+    fn.set_name("Alexander");
+    fn.set_surname("Zhirov");
+    fn.set_patronymic("Alexandrovich");
+
+    exercise_2::Student s;
+    *s.mutable_name() = fn;
+    s.add_grades(5);
+    s.add_grades(2);
+    s.add_grades(4);
+    s.add_grades(3);
+    s.add_grades(4);
+    s.add_grades(3);
+    s.add_grades(4);
+    s.add_grades(3);
+    s.set_avg_score(std::accumulate(s.grades().begin(), s.grades().end(), 0) / s.grades().size());
+
+    SG::StudentsGroup sg;
+    sg.add_student(s);
+    sg.Save();
+
+    SG::StudentsGroup new_sg;
+    new_sg.Open();
+    std:: cout << new_sg.GetAllInfo(fn) << std::endl;
+}
+
diff --git a/lesson_7/exercise_3.hpp b/lesson_7/exercise_3.hpp
new file mode 100644
index 0000000..aa0a33a
--- /dev/null
+++ b/lesson_7/exercise_3.hpp
@@ -0,0 +1,127 @@
+/*
+ * exercise_3.hpp
+ *
+ *  Created on: 15 окт. 2021 г.
+ *      Author: alexander
+ */
+
+#pragma once
+
+#include <iostream>
+#include <vector>
+#include <fstream>
+#include "src-gen/exercise_2.pb.h"
+
+namespace SG
+{
+    class IRepository
+    {
+    public:
+        virtual void Open() = 0; // бинарная десериализация в файл
+        virtual void Save() = 0; // бинарная сериализация в файл
+        virtual ~IRepository() {};
+    };
+
+    class IMethods
+    {
+    public:
+        virtual double GetAverageScore(const exercise_2::FullName &name) = 0;
+        virtual std::string GetAllInfo(const exercise_2::FullName &name) = 0;
+        virtual std::string GetAllInfo() = 0;
+        virtual ~IMethods() {};
+    };
+
+    class StudentsGroup: public IRepository, public IMethods
+    {
+    private:
+        std::vector<exercise_2::Student> m_students;
+    public:
+        void add_student(const exercise_2::Student &s)
+        {
+            m_students.push_back(s);
+        }
+
+        double GetAverageScore(const exercise_2::FullName &name)
+        {
+            auto it = std::find_if(m_students.begin(), m_students.end(), [&](const exercise_2::Student &s)
+            {
+                return tie(s.name().name(), s.name().surname(), s.name().patronymic()) ==
+                tie(name.name(), name.surname(), name.patronymic());
+            });
+
+            if (it == m_students.end())
+            {
+                return 0.0;
+            }
+
+            return it->avg_score();
+        }
+
+        std::string GetAllInfo(const exercise_2::FullName &name)
+        {
+            auto it = std::find_if(m_students.begin(), m_students.end(), [&](const exercise_2::Student &s)
+            {
+                return tie(s.name().name(), s.name().surname(), s.name().patronymic()) ==
+                tie(name.name(), name.surname(), name.patronymic());
+            });
+
+            if (it == m_students.end())
+            {
+                return {};
+            }
+
+            std::string temp = "Имя: " + it->name().name() + ' ' + it->name().surname() + ' ' + it->name().patronymic() + '\n';
+            temp += "Оценки: ";
+            for (int i = 0; i < it->grades().size(); ++i)
+            {
+                temp += std::to_string(it->grades(i)) + "; ";
+            }
+            temp += '\n';
+            temp += "Средний балл: " + std::to_string(it->avg_score()) + "\n\n";
+
+            return temp;
+        }
+
+        std::string GetAllInfo()
+        {
+            std::string temp;
+
+            std::for_each(m_students.begin(), m_students.end(), [&](const exercise_2::Student &s)
+            {
+                temp += GetAllInfo(s.name());
+            });
+
+            return temp;
+        }
+
+        void Save()
+        {
+            std::ofstream out("data.bin", std::ios_base::binary);
+            auto size = m_students.size();
+            out.write(reinterpret_cast<char*>(&size), sizeof(size));
+            std::for_each(m_students.begin(), m_students.end(), [&](const exercise_2::Student &s)
+            {
+                s.SerializeToOstream(&out);
+            });
+            out.close();
+        }
+
+        void Open()
+        {
+            std::ifstream in("data.bin", std::ios_base::binary);
+            size_t size = 0;
+            in.read(reinterpret_cast<char*>(&size), sizeof(size));
+            while (size--)
+            {
+                exercise_2::Student s;
+                s.ParseFromIstream(&in);
+                m_students.push_back(std::move(s));
+            }
+            in.close();
+        }
+
+        virtual ~StudentsGroup() {};
+    };
+}
+
+void exercise_3();
diff --git a/lesson_7/main.cpp b/lesson_7/main.cpp
index 976839a..58b14e7 100644
--- a/lesson_7/main.cpp
+++ b/lesson_7/main.cpp
@@ -5,47 +5,13 @@
  *      Author: alexander
  */
 
-#include <iostream>
-#include <numeric>
-#include <fstream>
-#include "src-gen/exercise_2.pb.h"
+#include "exercise_2.hpp"
+#include "exercise_3.hpp"
 
 int main()
 {
-//    exercise_2::FullName fn;
-//    fn.set_name("Alexander");
-//    fn.set_surname("Zhirov");
-//    fn.set_patronymic("Alexandrovich");
-//
-//    exercise_2::Student s;
-//    s.set_allocated_name(&fn);
-//    s.add_grades(5);
-//    s.add_grades(2);
-//    s.add_grades(4);
-//    s.add_grades(3);
-//    s.add_grades(4);
-//    s.add_grades(3);
-//    s.add_grades(4);
-//    s.add_grades(3);
-//    s.set_avg_score(std::accumulate(s.grades().begin(), s.grades().end(), 0) / s.grades().size());
-//
-//    exercise_2::StudentsGroup sg;
-//    *sg.add_students() = s;
-//
-//    std::ofstream out("student.bin", std::ios_base::binary);
-//    sg.SerializeToOstream(&out);
-
-    exercise_2::StudentsGroup sg;
-    std::ifstream in("student.bin", std::ios_base::binary);
-    if (sg.ParseFromIstream(&in))
-    {
-        std::cout << sg.students(0).name().surname() << std::endl;
-        std::cout << sg.students(0).avg_score() << std::endl;
-    }
-    else
-    {
-        std::cout << "Error!" << std::endl;
-    }
+    exercise_1_2();
+    exercise_3();
 
     return 0;
 }