diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..af235cf
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,46 @@
+cmake_minimum_required(VERSION 3.15)
+
+project(CalculatorApp LANGUAGES CXX)
+
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+# ------------------------------
+# ��������� ������������
+# ------------------------------
+add_executable(calc
+    src/main.cpp
+    src/calculator.cpp
+    src/plugin_manager.cpp
+)
+
+target_include_directories(calc PRIVATE src)
+
+# ------------------------------
+# ����� ��� DLL-��������
+# ------------------------------
+set(PLUGIN_OUTPUT_DIR ${CMAKE_BINARY_DIR}/plugins)
+file(MAKE_DIRECTORY ${PLUGIN_OUTPUT_DIR})
+
+# ------------------------------
+# ������ ��� ������ ������ �������
+# ------------------------------
+function(add_calc_plugin NAME SRCFILE)
+    add_library(${NAME} SHARED ${SRCFILE})
+    set_target_properties(${NAME} PROPERTIES
+        RUNTIME_OUTPUT_DIRECTORY ${PLUGIN_OUTPUT_DIR}
+        LIBRARY_OUTPUT_DIRECTORY ${PLUGIN_OUTPUT_DIR}
+        ARCHIVE_OUTPUT_DIRECTORY ${PLUGIN_OUTPUT_DIR}
+    )
+endfunction()
+
+# ------------------------------
+# ������� (������ DLL)
+# ------------------------------
+add_calc_plugin(funcsin   plugins_src/funcsin.cpp)
+add_calc_plugin(funcln    plugins_src/funcln.cpp)
+
+# ------------------------------
+# ��������� ����� ������
+# ------------------------------
+message(STATUS "Plugins will be placed in: ${PLUGIN_OUTPUT_DIR}")
diff --git a/plugins_src/funcln.cpp b/plugins_src/funcln.cpp
new file mode 100644
index 0000000..7e73219
--- /dev/null
+++ b/plugins_src/funcln.cpp
@@ -0,0 +1,33 @@
+// funcln.cpp
+// Êîìïèëèðîâàòü â DLL: cl /LD /std:c++17 funcln.cpp /Fe:funcln.dll
+// Èëè: g++ -shared -o funcln.dll funcln.cpp -Wl,--out-implib,libfuncln.a
+
+#include <cmath>
+#include <stdexcept>
+
+extern "C" {
+
+    struct PluginDescriptor {
+        const char* name;
+        int arity;
+        double(__cdecl* func)(const double* args, int argc);
+    };
+
+    static double __cdecl ln_impl(const double* args, int argc) {
+        if (argc != 1) throw std::runtime_error("ln expects 1 argument");
+        double x = args[0];
+        if (x <= 0.0) throw std::runtime_error("ln domain error: argument must be > 0");
+        return std::log(x);
+    }
+
+    static PluginDescriptor descriptor = {
+        "ln",
+        1,
+        ln_impl
+    };
+
+    __declspec(dllexport) PluginDescriptor* __cdecl register_plugin() {
+        return &descriptor;
+    }
+
+} // extern "C"
diff --git a/plugins_src/funcsin.cpp b/plugins_src/funcsin.cpp
new file mode 100644
index 0000000..6b5e784
--- /dev/null
+++ b/plugins_src/funcsin.cpp
@@ -0,0 +1,29 @@
+#include <cmath>
+#include <stdexcept>
+
+extern "C" {
+
+    struct PluginDescriptor {
+        const char* name;
+        int arity;
+        double(__cdecl* func)(const double*, int);
+    };
+    
+    static double __cdecl sin_deg(const double* args, int argc) {
+        const double pi = std::acos(-1);
+        if (argc != 1) throw std::runtime_error("sin expects 1 argument");
+        double radians = args[0] * pi / 180.0;
+        return std::sin(radians);
+    }
+
+    static PluginDescriptor desc = { 
+        "sin", 
+        1, 
+        sin_deg
+    };
+
+    __declspec(dllexport) PluginDescriptor* __cdecl register_plugin() {
+        return &desc;
+    }
+
+}
diff --git a/src/calculator.cpp b/src/calculator.cpp
new file mode 100644
index 0000000..0744af0
--- /dev/null
+++ b/src/calculator.cpp
@@ -0,0 +1,146 @@
+#include "calculator.h"
+#include <cctype>
+#include <cmath>
+#include <stdexcept>
+#include <iostream>
+#include <algorithm>
+
+using namespace std;
+
+Calculator::Calculator(const PluginManager& pm) : plugins(pm) {}
+
+Token Calculator::getNextToken() {
+    while (pos < input.size() && isspace(input[pos])) pos++;
+    if (pos >= input.size()) return { TokenKind::End, 0, "" };
+
+    char c = input[pos];
+
+    if (isdigit(c) || c == '.') {
+        size_t start = pos;
+        while (pos < input.size() && (isdigit(input[pos]) || input[pos] == '.')) pos++;
+        double val = stod(input.substr(start, pos - start));
+        return { TokenKind::Number, val, "" };
+    }
+
+    pos++;
+    switch (c) {
+    case '+': return { TokenKind::Plus };
+    case '-': return { TokenKind::Minus };
+    case '*': return { TokenKind::Mul };
+    case '/': return { TokenKind::Div };
+    case '(': return { TokenKind::LParen };
+    case ')': return { TokenKind::RParen };
+    case ',': return { TokenKind::Comma };
+    default:
+        if (isalpha(c)) {
+            size_t start = pos - 1;
+            while (pos < input.size() && (isalpha(input[pos]) || isdigit(input[pos]))) pos++;
+            string text = input.substr(start, pos - start);
+            return { TokenKind::Identifier, 0, text };
+        }
+        throw runtime_error(string("Unknown character: ") + c);
+    }
+}
+
+double Calculator::evaluate(const string& expr) {
+    input = expr;
+    pos = 0;
+    double res = parseExpression();
+
+    Token t = getNextToken();
+    if (t.kind != TokenKind::End)
+        throw runtime_error("Unexpected characters at end of expression");
+
+    return res;
+}
+
+double Calculator::parseExpression() {
+    double left = parseTerm();
+    while (true) {
+        size_t backup = pos;
+        Token t = getNextToken();
+        if (t.kind == TokenKind::Plus)
+            left += parseTerm();
+        else if (t.kind == TokenKind::Minus)
+            left -= parseTerm();
+        else {
+            pos = backup;
+            break;
+        }
+    }
+    return left;
+}
+
+double Calculator::parseTerm() {
+    double left = parseFactor();
+    while (true) {
+        size_t backup = pos;
+        Token t = getNextToken();
+        if (t.kind == TokenKind::Mul)
+            left *= parseFactor();
+        else if (t.kind == TokenKind::Div) {
+            double r = parseFactor();
+            if (r == 0) throw runtime_error("Division by zero");
+            left /= r;
+        }
+        else {
+            pos = backup;
+            break;
+        }
+    }
+    return left;
+}
+
+double Calculator::parseFactor() {
+    return parsePrimary();
+}
+
+double Calculator::parsePrimary() {
+    Token t = getNextToken();
+
+    if (t.kind == TokenKind::Number)
+        return t.value;
+
+    if (t.kind == TokenKind::Minus)
+        return -parsePrimary();
+
+    if (t.kind == TokenKind::LParen) {
+        double val = parseExpression();
+        Token r = getNextToken();
+        if (r.kind != TokenKind::RParen)
+            throw runtime_error("Missing ')'");
+        return val;
+    }
+
+    if (t.kind == TokenKind::Identifier) {
+        string fname = t.text;
+        transform(fname.begin(), fname.end(), fname.begin(), ::tolower);
+
+        Token next = getNextToken();
+        if (next.kind != TokenKind::LParen)
+            throw runtime_error("Expected '(' after function name");
+
+        vector<double> args;
+
+        size_t backup = pos;
+        Token lookahead = getNextToken();
+        if (lookahead.kind == TokenKind::RParen) {
+        }
+        else {
+            pos = backup;
+            args.push_back(parseExpression());
+            while (true) {
+                Token comma = getNextToken();
+                if (comma.kind == TokenKind::RParen)
+                    break;
+                if (comma.kind != TokenKind::Comma)
+                    throw runtime_error("Expected ',' or ')'");
+                args.push_back(parseExpression());
+            }
+        }
+
+        return plugins.callFunction(fname, args);
+    }
+
+    throw runtime_error("Unexpected token in expression");
+}
diff --git a/src/calculator.h b/src/calculator.h
new file mode 100644
index 0000000..238a696
--- /dev/null
+++ b/src/calculator.h
@@ -0,0 +1,20 @@
+#pragma once
+#include "plugin_manager.h"
+#include "token.h"
+#include <string>
+
+class Calculator {
+public:
+    Calculator(const PluginManager& pm);
+    double evaluate(const std::string& expr);
+private:
+    const PluginManager& plugins;
+    size_t pos;
+    std::string input;
+
+    Token getNextToken();
+    double parseExpression();
+    double parseTerm();
+    double parseFactor();
+    double parsePrimary();
+};
diff --git a/src/main.cpp b/src/main.cpp
new file mode 100644
index 0000000..768f8c8
--- /dev/null
+++ b/src/main.cpp
@@ -0,0 +1,28 @@
+#include "plugin_manager.h"
+#include "calculator.h"
+#include <iostream>
+#include <string>
+
+int main() {
+    PluginManager plugins;
+    plugins.loadPlugins("./plugins");
+    plugins.listFunctions();
+
+    Calculator calc(plugins);
+
+    std::string expr;
+    std::cout << "Enter expression (empty to quit):\n";
+    while (true) {
+        std::cout << "> ";
+        std::getline(std::cin, expr);
+        if (expr.empty()) break;
+
+        try {
+            double result = calc.evaluate(expr);
+            std::cout << result << "\n";
+        }
+        catch (const std::exception& e) {
+            std::cerr << "Error: " << e.what() << "\n";
+        }
+    }
+}
diff --git a/src/plugin_manager.cpp b/src/plugin_manager.cpp
new file mode 100644
index 0000000..cca1674
--- /dev/null
+++ b/src/plugin_manager.cpp
@@ -0,0 +1,87 @@
+#include "plugin_manager.h"
+#include <windows.h>
+#include <iostream>
+#include <filesystem>
+#include <algorithm>
+
+using namespace std;
+namespace fs = std::filesystem;
+
+void PluginManager::loadPlugins(const string& directory) {
+    functions.clear();
+
+    if (!fs::exists(directory)) {
+        cerr << "Plugins folder not found: " << directory << endl;
+        return;
+    }
+
+    for (auto& entry : fs::directory_iterator(directory)) {
+        if (entry.is_regular_file() && entry.path().extension() == ".dll") {
+            string path = entry.path().string();
+            HMODULE h = LoadLibraryA(path.c_str());
+            if (!h) {
+                cerr << "Failed to load plugin: " << path << endl;
+                continue;
+            }
+
+            auto reg = (PluginDescriptor * (__cdecl*)())GetProcAddress(h, "register_plugin");
+            if (!reg) {
+                cerr << "register_plugin not found in " << path << endl;
+                FreeLibrary(h);
+                continue;
+            }
+
+            try {
+                PluginDescriptor* desc = reg();
+                if (desc) {
+                    string name = desc->name ? desc->name : "";
+                    transform(name.begin(), name.end(), name.begin(), ::tolower);
+                    functions[name] = *desc;
+                    cout << "Loaded plugin: " << name
+                        << " (arity " << desc->arity << ")" << endl;
+                }
+            }
+            catch (const exception& e) {
+                cerr << "Error in plugin " << path << ": " << e.what() << endl;
+                FreeLibrary(h);
+            }
+        }
+    }
+
+    if (functions.empty())
+        cerr << "Warning: no plugins loaded from " << directory << endl;
+}
+
+bool PluginManager::hasFunction(const string& name) const {
+    string key = name;
+    transform(key.begin(), key.end(), key.begin(), ::tolower);
+    return functions.find(key) != functions.end();
+}
+
+double PluginManager::callFunction(const string& name,
+    const vector<double>& args) const {
+    string key = name;
+    transform(key.begin(), key.end(), key.begin(), ::tolower);
+    auto it = functions.find(key);
+    if (it == functions.end())
+        throw runtime_error("Unknown function: " + name);
+
+    const auto& f = it->second;
+    if ((int)args.size() != f.arity)
+        throw runtime_error("Function '" + name + "' expects " +
+            to_string(f.arity) + " arguments");
+
+    try {
+        return f.func(args.data(), (int)args.size());
+    }
+    catch (const exception& e) {
+        throw runtime_error("Error in function '" + name + "': " + e.what());
+    }
+}
+
+void PluginManager::listFunctions() const {
+    cout << "Available functions: ";
+    for (auto& [name, _] : functions)
+        cout << name << " ";
+    cout << endl;
+}
diff --git a/src/plugin_manager.h b/src/plugin_manager.h
new file mode 100644
index 0000000..a012305
--- /dev/null
+++ b/src/plugin_manager.h
@@ -0,0 +1,21 @@
+#pragma once
+#include <string>
+#include <unordered_map>
+#include <functional>
+#include <vector>
+
+struct PluginDescriptor {
+    const char* name;
+    int arity;
+    double(__cdecl* func)(const double* args, int argc);
+};
+
+class PluginManager {
+public:
+    void loadPlugins(const std::string& directory);
+    bool hasFunction(const std::string& name) const;
+    double callFunction(const std::string& name, const std::vector<double>& args) const;
+    void listFunctions() const;
+private:
+    std::unordered_map<std::string, PluginDescriptor> functions;
+};
diff --git a/src/token.h b/src/token.h
new file mode 100644
index 0000000..a516c1d
--- /dev/null
+++ b/src/token.h
@@ -0,0 +1,17 @@
+#pragma once
+#include <string>
+
+enum class TokenKind {
+    Number,
+    Plus, Minus, Mul, Div,
+    LParen, RParen,
+    Comma,
+    Identifier,
+    End
+};
+
+struct Token {
+    TokenKind kind;
+    double value;
+    std::string text;
+};