diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..d6b116d
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,116 @@
+set(PROJECT_NAME quadratic)
+
+################################################################################
+# Source groups
+################################################################################
+set(Source_Files
+    "main.cpp"
+    "quadratic.cpp"
+    "quadratic.h"
+)
+source_group("Source Files" FILES ${Source_Files})
+
+set(ALL_FILES
+    ${Source_Files}
+)
+
+################################################################################
+# Target
+################################################################################
+add_executable(${PROJECT_NAME} ${ALL_FILES})
+
+use_props(${PROJECT_NAME} "${CMAKE_CONFIGURATION_TYPES}" "${DEFAULT_CXX_PROPS}")
+set(ROOT_NAMESPACE quadratic)
+
+set_target_properties(${PROJECT_NAME} PROPERTIES
+    VS_GLOBAL_KEYWORD "Win32Proj"
+)
+if("${CMAKE_VS_PLATFORM_NAME}" STREQUAL "x64")
+    set_target_properties(${PROJECT_NAME} PROPERTIES
+        INTERPROCEDURAL_OPTIMIZATION_RELEASE "TRUE"
+    )
+elseif("${CMAKE_VS_PLATFORM_NAME}" STREQUAL "x86")
+    set_target_properties(${PROJECT_NAME} PROPERTIES
+        INTERPROCEDURAL_OPTIMIZATION_RELEASE "TRUE"
+    )
+endif()
+################################################################################
+# Compile definitions
+################################################################################
+if("${CMAKE_VS_PLATFORM_NAME}" STREQUAL "x64")
+    target_compile_definitions(${PROJECT_NAME} PRIVATE
+        "$<$<CONFIG:Debug>:"
+            "_DEBUG"
+        ">"
+        "$<$<CONFIG:Release>:"
+            "NDEBUG"
+        ">"
+        "_CONSOLE;"
+        "UNICODE;"
+        "_UNICODE"
+    )
+elseif("${CMAKE_VS_PLATFORM_NAME}" STREQUAL "x86")
+    target_compile_definitions(${PROJECT_NAME} PRIVATE
+        "$<$<CONFIG:Debug>:"
+            "_DEBUG"
+        ">"
+        "$<$<CONFIG:Release>:"
+            "NDEBUG"
+        ">"
+        "WIN32;"
+        "_CONSOLE;"
+        "UNICODE;"
+        "_UNICODE"
+    )
+endif()
+
+################################################################################
+# Compile and link options
+################################################################################
+if(MSVC)
+    if("${CMAKE_VS_PLATFORM_NAME}" STREQUAL "x64")
+        target_compile_options(${PROJECT_NAME} PRIVATE
+            $<$<CONFIG:Release>:
+                /Oi;
+                /Gy
+            >
+            /permissive-;
+            /sdl;
+            /W3;
+            ${DEFAULT_CXX_DEBUG_INFORMATION_FORMAT};
+            ${DEFAULT_CXX_EXCEPTION_HANDLING}
+        )
+    elseif("${CMAKE_VS_PLATFORM_NAME}" STREQUAL "x86")
+        target_compile_options(${PROJECT_NAME} PRIVATE
+            $<$<CONFIG:Release>:
+                /Oi;
+                /Gy
+            >
+            /permissive-;
+            /sdl;
+            /W3;
+            ${DEFAULT_CXX_DEBUG_INFORMATION_FORMAT};
+            ${DEFAULT_CXX_EXCEPTION_HANDLING}
+        )
+    endif()
+    if("${CMAKE_VS_PLATFORM_NAME}" STREQUAL "x64")
+        target_link_options(${PROJECT_NAME} PRIVATE
+            $<$<CONFIG:Release>:
+                /OPT:REF;
+                /OPT:ICF
+            >
+            /DEBUG;
+            /SUBSYSTEM:CONSOLE
+        )
+    elseif("${CMAKE_VS_PLATFORM_NAME}" STREQUAL "x86")
+        target_link_options(${PROJECT_NAME} PRIVATE
+            $<$<CONFIG:Release>:
+                /OPT:REF;
+                /OPT:ICF
+            >
+            /DEBUG;
+            /SUBSYSTEM:CONSOLE
+        )
+    endif()
+endif()
+
diff --git a/main.cpp b/main.cpp
new file mode 100644
index 0000000..ded908c
--- /dev/null
+++ b/main.cpp
@@ -0,0 +1,28 @@
+#include "quadratic.h"
+
+int main() {
+    std::cout << "Programm for find value ax^2 + bx + c = 0\n";
+    while (true) {
+        try {
+            double a = getValidCoefficient("a: ");
+            double b = getValidCoefficient("b: ");
+            double c = getValidCoefficient("c: ");
+
+            solveQuadratic(a, b, c);
+
+            std::cout << "\nWould you like more? (yes/no): ";
+            std::string answer;
+            std::cin >> answer;
+
+            if (answer != "yes") {
+                std::cout << "Thanks for using programm.\n";
+                break;
+            }
+        }
+        catch (const std::exception& e) {
+            std::cerr << "Error: " << e.what() << "\n";
+        }
+    }
+
+    return 0;
+}
\ No newline at end of file
diff --git a/quadratic.cpp b/quadratic.cpp
new file mode 100644
index 0000000..a809a3e
--- /dev/null
+++ b/quadratic.cpp
@@ -0,0 +1,38 @@
+#include "quadratic.h"
+
+void solveQuadratic(double a, double b, double c) {
+    if (a == 0) {
+        throw std::invalid_argument("'a' != 0 !");
+    }
+
+    double discriminant = b * b - 4 * a * c;
+
+    if (discriminant > 0) {
+        double root1 = (-b + std::sqrt(discriminant)) / (2 * a);
+        double root2 = (-b - std::sqrt(discriminant)) / (2 * a);
+        std::cout << "x1 = " << root1 << "\n";
+        std::cout << "x2 = " << root2 << "\n";
+    }
+    else if (discriminant == 0) {
+        double root = -b / (2 * a);
+        std::cout << "x = " << root << "\n";
+    }
+    else {
+        std::cout << "complex value.\n";
+    }
+}
+
+double getValidCoefficient(const std::string& prompt) {
+    double coefficient;
+    while (true) {
+        std::cout << prompt;
+        if (std::cin >> coefficient) {
+            return coefficient;
+        }
+        else {
+            std::cout << "Error: not number.\n";
+            std::cin.clear();
+            std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
+        }
+    }
+}
\ No newline at end of file
diff --git a/quadratic.h b/quadratic.h
new file mode 100644
index 0000000..5590f36
--- /dev/null
+++ b/quadratic.h
@@ -0,0 +1,12 @@
+#ifndef QUADRATIC_H
+#define QUADRATIC_H
+
+#include <iostream>
+#include <cmath>
+#include <stdexcept>
+
+void solveQuadratic(double a, double b, double c);
+
+double getValidCoefficient(const std::string& prompt);
+
+#endif // QUADRATIC_H
\ No newline at end of file