diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..f0ebdb7
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,7 @@
+cmake_minimum_required(VERSION 3.12)
+project(networks-labs)
+
+set(CMAKE_CXX_STANDARD 17)
+
+#add_subdirectory(CalculatorServer)
+add_subdirectory(CalculatorClient)
\ No newline at end of file
diff --git a/CalculatorClient/CMakeLists.txt b/CalculatorClient/CMakeLists.txt
new file mode 100644
index 0000000..010a53b
--- /dev/null
+++ b/CalculatorClient/CMakeLists.txt
@@ -0,0 +1,11 @@
+project(Calculator)
+
+SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pthread")
+
+add_executable(${PROJECT_NAME} src/main.cpp src/calc_client.hpp src/protocol.hpp src/operations.hpp)
+
+#target_link_libraries(${PROJECT_NAME} EmailCommon ${TBB_IMPORTED_TARGETS})
+
+target_include_directories(${PROJECT_NAME}
+        PUBLIC ${PROJECT_SOURCE_DIR}/include
+        )
\ No newline at end of file
diff --git a/CalculatorClient/src/calc_client.hpp b/CalculatorClient/src/calc_client.hpp
new file mode 100644
index 0000000..00dfa52
--- /dev/null
+++ b/CalculatorClient/src/calc_client.hpp
@@ -0,0 +1,89 @@
+#include <netinet/in.h>
+#include <netdb.h>
+#include <cstdio>
+#include <cstdlib>
+#include <string.h>
+#include <string>
+#include <memory>
+#include "operations.hpp"
+#include "protocol.hpp"
+#include <sys/socket.h>
+#include <iostream>
+
+using std::string;
+
+
+using namespace operations;
+
+struct CalcClient {
+
+
+    CalcClient(const char *hostname, uint16_t port) {
+        sockaddr_in serv_addr;
+        hostent *server;
+
+        sock_desc = socket(AF_INET, SOCK_STREAM, 0);
+
+        if (sock_desc < 0) {
+            perror("ERROR opening socket");
+            exit(1);
+        }
+
+        server = gethostbyname(hostname);
+
+        if (server == nullptr) {
+            fprintf(stderr, "ERROR, no such host\n");
+            exit(0);
+        }
+
+        bzero((char *) &serv_addr, sizeof(serv_addr));
+        serv_addr.sin_family = AF_INET;
+        bcopy(server->h_addr, (char *) &serv_addr.sin_addr.s_addr, (size_t) server->h_length);
+        serv_addr.sin_port = htons(port);
+
+        if (connect(sock_desc, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) {
+            perror("ERROR connecting");
+            exit(1);
+        }
+    }
+
+    void execute(const string &type, int32_t arg1, int32_t arg2) {
+        Type req = operations::typeFromString(type);
+        protocol::Response *response = doRequest(req, arg1, arg2);
+
+        if (response->getStatus() == protocol::status::Ok) {
+            std::cout << "Evaluation result: " << (static_cast<protocol::Ok *>(response))->getResult();
+        } else {
+            std::cout << "Wrong result :c" << std::endl;
+        }
+
+        delete response;
+    }
+
+private:
+    protocol::Response *doRequest(operations::Type type, int32_t arg1, int32_t arg2) {
+        char *buffer = new char[protocol::REQUEST_SIZE];
+        switch (type) {
+            case Fact:
+            case Sq: {
+                protocol::LongOperationRequest(arg1, arg2, type).toCharArray(buffer);
+            };
+
+            case Add:
+            case Subs:
+            case Div:
+            case Mult: {
+                protocol::QuickOperationRequest(arg1, arg2, type).toCharArray(buffer);
+            }
+                ssize_t i = -1;
+                while (i < protocol::REQUEST_SIZE) {
+                    i = send(sock_desc, buffer + i, protocol::REQUEST_SIZE - i, 0);
+                }
+                return protocol::parseResult(sock_desc);
+        }
+    }
+
+
+private:
+    int sock_desc;
+};
\ No newline at end of file
diff --git a/CalculatorClient/src/main.cpp b/CalculatorClient/src/main.cpp
new file mode 100644
index 0000000..f61fde3
--- /dev/null
+++ b/CalculatorClient/src/main.cpp
@@ -0,0 +1,60 @@
+#include <iostream>
+#include <sstream>
+#include "calc_client.hpp"
+
+
+int main() {
+    std::cout << "Hello in calculator client!" << std::endl;
+
+    string host;
+
+    std::cout << "Enter server address" << std::endl;
+    getline(std::cin, host);
+
+
+    uint16_t port;
+    std::cout << "Enter server port" << std::endl;
+
+    std::string input;
+    getline(std::cin, input);
+    if (!input.empty()) {
+        std::istringstream stream(input);
+        stream >> port;
+    }
+
+    CalcClient client(host.c_str(), port);
+
+    while (true) {
+
+        string command;
+
+        int32_t arg1, arg2;
+
+        std::cout << "Enter one of comands: fact, square, sub, add, mult, div, exit " << std::endl;
+
+        getline(std::cin, command);
+        if (command == "exit") {
+            std::cout << "Exit.";
+            break;
+        }
+
+        std::string arg_input;
+        std::cout << "Enter first arg" << std::endl;
+        getline(std::cin, arg_input);
+        if (!arg_input.empty()) {
+            std::istringstream stream(arg_input);
+            stream >> arg1;
+        }
+
+        std::cout << "Enter second arg" << std::endl;
+        getline(std::cin, arg_input);
+        if (!arg_input.empty()) {
+            std::istringstream stream(arg_input);
+            stream >> arg2;
+        }
+
+        client.execute(command, arg1, arg2);
+    }
+
+    return 0;
+}
\ No newline at end of file
diff --git a/CalculatorClient/src/operations.hpp b/CalculatorClient/src/operations.hpp
new file mode 100644
index 0000000..252b4a8
--- /dev/null
+++ b/CalculatorClient/src/operations.hpp
@@ -0,0 +1,69 @@
+#include <cstdint>
+#include <cmath>
+#include <unistd.h>
+#include <cstdio>
+#include <string>
+
+#pragma once
+namespace operations {
+    using std::string;
+    enum Type {
+        Fact = 1,
+        Sq = 2,
+        Add = 3,
+        Subs = 4,
+        Mult = 5,
+        Div = 6
+    };
+
+
+    Type typeFromString(const string &text) {
+        if (text == "fact") {
+            return Fact;
+        }
+
+        if (text == "sq") {
+            return Sq;
+        }
+
+        if (text == "add") {
+            return Add;
+        }
+
+        if (text == "sub") {
+            return Subs;
+        }
+
+        if (text == "mul") {
+            return Mult;
+        }
+
+        if (text == "div") {
+            return Div;
+        }
+
+        perror("Invalid operation type");
+    };
+
+    string stringFromType(Type type) {
+        switch (type) {
+            case Type::Fact :
+                return "factorial";
+            case Type::Sq:
+                return "square";
+            case Type::Add:
+                return "addition";
+            case Subs:
+                return "substract";
+            case Mult:
+                return "multiplication";
+            case Div:
+                return "division";
+            default:
+                perror("");
+        }
+    }
+
+}
+
+
diff --git a/CalculatorClient/src/protocol.hpp b/CalculatorClient/src/protocol.hpp
new file mode 100644
index 0000000..89385ca
--- /dev/null
+++ b/CalculatorClient/src/protocol.hpp
@@ -0,0 +1,142 @@
+#include "operations.hpp"
+#include <memory>
+#include <string>
+#include <cstring>
+
+namespace protocol {
+    // result -- 4 bytes
+    // opertaion type -- 1 byte
+    // status -- 1 byte
+    // or 1 byte for status
+    const size_t MAX_RESPONSE_SIZE = 4 + 1 + 1;
+
+    // arg1 -- 4 bytes
+    // arg2 or executation time -- 4 bytes
+    // opertation type -- 1 byte
+    const size_t REQUEST_SIZE = 4 + 4 + 1;
+
+    struct Request {
+        explicit Request(operations::Type type) : type_(type) {}
+
+        virtual void toCharArray(char *buffer) = 0;
+
+    protected:
+        const operations::Type type_;
+
+        void writeIntToCharArray(char *buffer, int32_t value, size_t startPosition) {
+            const size_t end = startPosition + 4;
+            for (size_t i = startPosition; i < end; ++i) {
+                buffer[i] = static_cast<uint8_t >(value & 0xffu);
+                value >>= 8;
+            }
+        }
+    };
+
+    struct LongOperationRequest : Request {
+        LongOperationRequest(int32_t param, int32_t time, operations::Type type) :
+                param_(param),
+                time_(time),
+                Request(type) {}
+
+
+        void toCharArray(char *buffer) override {
+            writeIntToCharArray(buffer, param_, 0);
+            writeIntToCharArray(buffer, time_, 0);
+            buffer[REQUEST_SIZE - 2] = type_;
+        }
+
+    private:
+        const int32_t param_;
+        const int32_t time_;
+
+    };
+
+    struct QuickOperationRequest : Request {
+        QuickOperationRequest(int32_t param1, int32_t param2, operations::Type type) :
+                param1_(param1),
+                param2_(param2),
+                Request(type) {}
+
+        void toCharArray(char *buffer) override {
+            writeIntToCharArray(buffer, param1_, 0);
+            writeIntToCharArray(buffer, param2_, 0);
+            buffer[REQUEST_SIZE - 2] = type_;
+        }
+
+    private:
+        const int32_t param1_;
+        const int32_t param2_;
+
+
+    };
+
+
+    int32_t parseInt(const char *buffer, const size_t start) {
+        int32_t result = buffer[start + 4 - 1];
+        for (size_t i = start + 4 - 1; i > start; --i) {
+            result <<= 8;
+            result += buffer[i - 1];
+        }
+        return result;
+    }
+
+
+    using namespace operations;
+
+    namespace status {
+        enum Status {
+            Ok = 0,
+            Fail = -1
+        };
+
+    }
+
+    struct Response {
+        explicit Response(status::Status stat) : stat_(stat) {};
+
+        status::Status getStatus() {
+            return stat_;
+        }
+
+    private:
+        const status::Status stat_;
+    };
+
+    struct Ok : public Response {
+        Ok(int32_t val, operations::Type type) : result_(val), type_(type), Response(status::Ok) {
+
+        }
+
+        int32_t getResult() {
+            return result_;
+        }
+
+    private:
+        int32_t result_;
+        operations::Type type_;
+    };
+
+    struct Fail : public Response {
+        Fail() :
+                Response(status::Fail) {};
+    };
+
+    Response *parseResult(const int socket) {
+        std::unique_ptr<char[]> buffer(new char[MAX_RESPONSE_SIZE]);
+
+        ssize_t ssize = 0;
+        while (ssize < MAX_RESPONSE_SIZE) {
+            if (ssize == 1 && buffer[0] == status::Fail) {
+                return new Fail();
+            }
+
+            ssize = read(socket, buffer.get() + ssize, MAX_RESPONSE_SIZE - ssize);
+        }
+
+        int32_t result = parseInt(buffer.get(), 0);
+        char &operationType = buffer[MAX_RESPONSE_SIZE - 2];
+
+        return new Ok(result, static_cast<Type>(operationType));
+    }
+
+}
\ No newline at end of file