initial

CMakeLists.txt

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+cmake_minimum_required(VERSION 3.26)
+project(threads)
+
+set(CMAKE_CXX_STANDARD 17)
+
+add_executable(threads main.cpp)

main.cpp

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+#include <iostream>
+#include <vector>
+#include <fstream>
+#include <string>
+#include <thread>
+
+std::vector<int> read_measurements(const std::string& filename);
+void parallel_measurements(std::vector<int> measurements);
+void serial_measurements(std::vector<int> measurements);
+
+int main() {
+    std::vector<int> measurements = read_measurements(R"(C:\Users\tilob\CLionProjects\threads\measurements.txt)");
+
+    // test parallel
+    auto start = std::chrono::steady_clock::now();
+    parallel_measurements(measurements);
+    auto end = std::chrono::steady_clock::now();
+    std::chrono::duration<double> diff = end - start;
+    std::cout << "Parallel Took: " << diff.count() << "s\n";
+
+    // test serial
+    start = std::chrono::steady_clock::now();
+    serial_measurements(measurements);
+    end = std::chrono::steady_clock::now();
+    diff = end - start;
+    std::cout << "Serial Took: " << diff.count() << "s\n";
+}
+
+void parallel_measurements(std::vector<int> measurements) {
+    int numThreads = 4;
+    std::vector<int> results(numThreads, 0);
+    std::vector<std::thread> threads;
+
+    int totalComparisons = measurements.size() - 1;
+    int base = totalComparisons / numThreads;
+    int remainder  = totalComparisons % numThreads;
+
+    int idx = 1;
+    for (int t = 0; t < numThreads; t++)
+    {
+        int startIdx = idx;
+
+        // wie viele Vergleiche dieser Thread macht
+        int count = base + (t < remainder ? 1 : 0);
+
+        int endIdx = idx + count - 1;
+        idx = endIdx + 1;
+
+        // Lambda-Funktion: definiert die Aufgabe, die dieser Thread ausführt
+        threads.emplace_back([&, t, startIdx, endIdx]()
+                             {
+                                 int localCount = 0;
+                                 for (int i = startIdx; i <= endIdx; ++i)
+                                     if (measurements[i] > measurements[i - 1])
+                                         ++localCount;
+
+                                 results[t] = localCount;
+                             });
+    }
+
+    // auf jeden Thread warten
+    for (auto &th : threads)
+        th.join();
+
+    // Ergebnisse aufsummieren
+    int total = 0;
+    for (int r : results)
+        total += r;
+
+    std::cout << "Anzahl steigender Messwerte (parallel): " << total << "\n";
+}
+
+std::vector<int> read_measurements(const std::string& filename) {
+    std::ifstream file(filename);
+    std::vector<int> result;
+
+    if (!file.is_open()) {
+        std::cerr << "Could not open file\n";
+        return result;
+    }
+
+    std::string line;
+    while (std::getline(file, line)) {
+        // Process each line
+        result.push_back(std::stoi(line));
+    }
+
+    return result;
+}
+
+void serial_measurements(std::vector<int> measurements) {
+    int result = 0;
+    for (size_t i = 1; i < measurements.size(); ++i) {
+        if (measurements[i] > measurements[i - 1])
+            ++result;
+    }
+}