exercise 3

lesson_6/Timer.hpp

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+/*
+ * Timer.hpp
+ *
+ *  Created on: 12 окт. 2021 г.
+ *      Author: alexander
+ */
+
+#pragma once
+
+#include <iostream>
+#include <chrono>
+
+class Timer
+{
+private:
+    using clock_t = std::chrono::high_resolution_clock;
+    using second_t = std::chrono::duration<double, std::ratio<1> >;
+
+    std::string m_name;
+    std::chrono::time_point<clock_t> m_beg;
+    double elapsed() const
+    {
+        return std::chrono::duration_cast<second_t>(clock_t::now() -m_beg).count();
+    }
+
+public:
+    Timer() : m_beg(clock_t::now()) { }
+    Timer(std::string name) : m_name(name), m_beg(clock_t::now()) { }
+
+    void start(std::string name) {
+        m_name = name;
+        m_beg = clock_t::now();
+    }
+    void print() const {
+        std::cout << m_name << ":\t" << elapsed() * 1000 << " ms" << '\n';
+    }
+};

lesson_6/exercise_1.hpp

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+/*
+ * exercise_1.hpp
+ *
+ *  Created on: 10 окт. 2021 г.
+ *      Author: alexander
+ */
+
+#pragma once
+
+#include <iostream>
+#include <thread>
+#include <mutex>
+
+static std::mutex mtx_cout;
+
+class pcout
+{
+private:
+    std::lock_guard<std::mutex> lg;
+public:
+    pcout() : lg(std::lock_guard<std::mutex>(mtx_cout))
+    {
+    }
+
+    template<typename T>
+    pcout& operator<<(const T &data)
+    {
+        std::cout << data;
+        return *this;
+    }
+
+    pcout& operator<<(std::ostream& (*fp)(std::ostream&))                // т.к. std::endl является функцией,
+    {                                                                    // то для неё делаем перегрузку operator<<
+        std::cout << fp;                                                 // которая принимает указатель на функцию
+        return *this;                                                    // типа std::ostream& и возвращает наш
+    }                                                                    // защищённый поток вывода
+};
+
+void doSomething(int number)
+{
+    pcout() << "start thread " << number << std::endl;
+    pcout() << "stop thread " << number << std::endl;
+}
+
+void exercise_1()
+{
+    std::thread th1(doSomething, 1);
+    std::thread th2(doSomething, 2);
+    std::thread th3(doSomething, 3);
+    th1.join();
+    th2.join();
+    th3.join();
+}

lesson_6/exercise_2.hpp

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+/*
+ * exercise_2.hpp
+ *
+ *  Created on: 11 окт. 2021 г.
+ *      Author: alexander
+ */
+
+#pragma once
+
+#include <iostream>
+#include <thread>
+#include <vector>
+#include <mutex>
+#include "Timer.hpp"
+
+bool isPrime(size_t num)
+{
+    size_t limit = num / 2;
+
+    if (num > 2)
+    {
+        for (size_t i = 2; i <= limit; ++i)
+        {
+            if (num % i == 0)
+            {
+                return false;
+            }
+        }
+    }
+
+    return true;
+}
+
+void exercise_2()
+{
+
+    size_t maxValue = 500000;
+    size_t counThreads = 30;
+    std::vector<size_t> answers;
+    std::mutex m;
+
+    Timer timer("With threads");
+
+    for (size_t i = 0; i < maxValue;)
+    {
+        std::vector<std::thread> v;
+
+        for (size_t j = i + counThreads; i <= j; ++i)
+        {
+            v.push_back(std::thread([=, &m, &answers]()
+            {
+                if (isPrime(i))
+                {
+                    std::lock_guard lg(m);
+                    answers.push_back(i);
+                }
+            }));
+        }
+
+        for (auto &t : v)
+        {
+            t.join();
+        }
+    }
+
+//    for (const auto &a : answers)
+//    {
+//        std::cout << "Число " << a << " простое" << std::endl;
+//    }
+
+    timer.print();
+
+    answers.clear();
+    answers.shrink_to_fit();
+
+    timer.start("Without threads");
+
+    for (size_t i = 0; i < maxValue; ++i)
+    {
+        if (isPrime(i))
+        {
+            answers.push_back(i);
+        }
+    }
+
+//    for (const auto &a : answers)
+//    {
+//        std::cout << "Число " << a << " простое" << std::endl;
+//    }
+
+    timer.print();
+}

lesson_6/exercise_3.hpp

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+/*
+ * exercise_3.hpp
+ *
+ *  Created on: 12 окт. 2021 г.
+ *      Author: alexander
+ */
+
+#pragma once
+
+#include <iostream>
+#include <vector>
+#include <thread>
+#include <mutex>
+#include <algorithm>
+#include <random>
+
+std::mutex m;
+
+void generate_things(std::vector<int> &v)
+{
+    std::random_device rd;
+    std::mt19937 mersenne(rd());
+    std::uniform_int_distribution<int> urd(0, 1000);
+
+    std::lock_guard lg(m);
+
+    std::generate(v.begin(), v.end(), [&]()
+    {
+        return urd(mersenne);
+    });
+}
+
+void pop_thing(std::vector<int> &v)
+{
+    std::lock_guard lg(m);
+
+    std::cout << *std::max_element(v.begin(), v.end()) << std::endl;
+}
+
+void exercise_3()
+{
+    std::vector<int> v(100);
+    size_t count = 100;
+
+    while (count--)
+    {
+        std::thread owner([&]()
+        {
+            generate_things(v);
+        });
+        std::thread thief([&]()
+        {
+            pop_thing(v);
+        });
+
+        owner.join();
+        thief.join();
+    }
+}

lesson_6/main.cpp

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+/*
+ * main.cpp
+ *
+ *  Created on: 10 окт. 2021 г.
+ *      Author: alexander
+ */
+#include "exercise_1.hpp"
+#include "exercise_2.hpp"
+#include "exercise_3.hpp"
+
+int main()
+{
+//    exercise_1();
+//    exercise_2();
+    exercise_3();
+
+    return 0;
+}