diff --git a/histogram.cpp b/histogram.cpp
index 8c8a080..ad249d2 100644
--- a/histogram.cpp
+++ b/histogram.cpp
@@ -4,7 +4,7 @@
 #include "histogram.h"
 #include "histogram_internal.h"
 using namespace std;
-void find_minmax(const vector<double>& numbers, double& min, double& max) {
+void find_minmax(const vector<double> numbers, double& min, double& max) {
     min = numbers[0];
     for (auto i = 0; i < numbers.size(); i++) {
         if (numbers[i] < min) {
diff --git a/histogram_internal.h b/histogram_internal.h
new file mode 100644
index 0000000..18abf25
--- /dev/null
+++ b/histogram_internal.h
@@ -0,0 +1,6 @@
+#ifndef HISTOGRAM_INTERNAL_H_INCLUDED
+#define HISTOGRAM_INTERNAL_H_INCLUDED
+#include <vector>
+void find_minmax(std::vector<double> numbers, double& min, double& max);
+
+#endif // HISTOGRAM_INTERNAL_H_INCLUDED
diff --git a/project3.layout b/project3.layout
new file mode 100644
index 0000000..5bf559e
--- /dev/null
+++ b/project3.layout
@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
+<CodeBlocks_layout_file>
+	<FileVersion major="1" minor="0" />
+	<ActiveTarget name="Debug" />
+	<File name="histogram.h" open="1" top="0" tabpos="3" split="0" active="1" splitpos="0" zoom_1="0" zoom_2="0">
+		<Cursor>
+			<Cursor1 position="175" topLine="0" />
+		</Cursor>
+	</File>
+	<File name="main.cpp" open="1" top="0" tabpos="1" split="0" active="1" splitpos="0" zoom_1="0" zoom_2="0">
+		<Cursor>
+			<Cursor1 position="99" topLine="0" />
+		</Cursor>
+	</File>
+	<File name="text.cpp" open="1" top="0" tabpos="6" split="0" active="1" splitpos="0" zoom_1="0" zoom_2="0">
+		<Cursor>
+			<Cursor1 position="77" topLine="0" />
+		</Cursor>
+	</File>
+	<File name="histogram.cpp" open="1" top="0" tabpos="4" split="0" active="1" splitpos="0" zoom_1="0" zoom_2="0">
+		<Cursor>
+			<Cursor1 position="160" topLine="0" />
+		</Cursor>
+	</File>
+</CodeBlocks_layout_file>
diff --git a/unitest.cbp b/unitest.cbp
new file mode 100644
index 0000000..b58cac2
--- /dev/null
+++ b/unitest.cbp
@@ -0,0 +1,36 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
+<CodeBlocks_project_file>
+	<FileVersion major="1" minor="6" />
+	<Project>
+		<Option title="unitest" />
+		<Option pch_mode="2" />
+		<Option compiler="gcc" />
+		<Build>
+			<Target title="Debug">
+				<Option output="bin/Debug/unitest" prefix_auto="1" extension_auto="1" />
+				<Option object_output="obj/Debug/" />
+				<Option type="1" />
+				<Option compiler="gcc" />
+				<Compiler>
+					<Add option="-g" />
+				</Compiler>
+			</Target>
+			<Target title="Release">
+				<Option output="bin/Release/unitest" prefix_auto="1" extension_auto="1" />
+				<Option object_output="obj/Release/" />
+				<Option type="1" />
+				<Option compiler="gcc" />
+				<Compiler>
+					<Add option="-O2" />
+				</Compiler>
+				<Linker>
+					<Add option="-s" />
+				</Linker>
+			</Target>
+		</Build>
+		<Compiler>
+			<Add option="-Wall" />
+		</Compiler>
+		<Extensions />
+	</Project>
+</CodeBlocks_project_file>
diff --git a/unitest.cpp b/unitest.cpp
new file mode 100644
index 0000000..28c1f8d
--- /dev/null
+++ b/unitest.cpp
@@ -0,0 +1,16 @@
+#define DOCTEST_CONFIG_NO_MULTITHREADING
+#define DOCTEST_CONFIG_IMPLEMENT_WITH_MAIN
+#include "doctest.h"
+#include "histogram_internal.h"
+#include <vector>
+TEST_CASE("distinct positive numbers") {
+    double min = 0;
+    double max = 0;
+ std::vector<double>mas{1,2};
+    CHECK(mas.size() != 0);
+    CHECK(mas.size() != 1);
+    find_minmax(mas, min, max);
+    CHECK(min == 1);
+    CHECK(max == 2);
+    CHECK(min != max);
+}
diff --git a/unitest.depend b/unitest.depend
new file mode 100644
index 0000000..3246a93
--- /dev/null
+++ b/unitest.depend
@@ -0,0 +1,64 @@
+# depslib dependency file v1.0
+1682275493 source:c:\users\hp\desktop\lab-03\project3\histogram.cpp
+	<iostream>
+	<vector>
+	<cmath>
+	"histogram.h"
+	"histogram_internal.h"
+
+1682271918 c:\users\hp\desktop\lab-03\project3\histogram.h
+	<vector>
+
+1682275464 c:\users\hp\desktop\lab-03\project3\histogram_internal.h
+	<vector>
+
+1682275379 source:c:\users\hp\desktop\lab-03\project3\unitest.cpp
+	"doctest.h"
+	"histogram_internal.h"
+	<vector>
+
+1682274805 c:\users\hp\desktop\lab-03\project3\doctest.h
+	<signal.h>
+	<ciso646>
+	<cstddef>
+	<ostream>
+	<istream>
+	<type_traits>
+	"doctest_fwd.h"
+	<ctime>
+	<cmath>
+	<climits>
+	<math.h>
+	<new>
+	<cstdio>
+	<cstdlib>
+	<cstring>
+	<limits>
+	<utility>
+	<fstream>
+	<sstream>
+	<iostream>
+	<algorithm>
+	<iomanip>
+	<vector>
+	<atomic>
+	<mutex>
+	<set>
+	<map>
+	<unordered_set>
+	<exception>
+	<stdexcept>
+	<csignal>
+	<cfloat>
+	<cctype>
+	<cstdint>
+	<string>
+	<sys/types.h>
+	<unistd.h>
+	<sys/sysctl.h>
+	<AfxWin.h>
+	<windows.h>
+	<io.h>
+	<sys/time.h>
+	<unistd.h>
+