timmyshen · August 29, 2014 02:49 · Aug 29, 2014
diff --git a/source.cpp b/source.cpp
@@ -0,0 +1,61 @@
+#include <iostream>
+#include <chrono>
+#include <random>
+
+int main(int argc, char* argv [])
+{
+    auto x = 1;
+    std::cout << "auto variable x = " << x << std::endl;
+
+    srand(0u);
+    auto r = rand();
+    std::cout << "rand() = " << r << std::endl;
+
+    std::cout << "next rand() = " << rand() << std::endl;
+
+    auto start = std::chrono::steady_clock::now();
+    int sum(0);
+    for (size_t i = 0; i < 10000000; i++)
+    {
+        sum += rand();
+    }
+    auto end = std::chrono::steady_clock::now();
+    auto span = end - start;
+    std::cout << "time span in seconds: " << span.count() << std::endl;
+    std::cout << "sum = " << sum << std::endl;
+
+
+    start = std::chrono::steady_clock::now();
+    std::default_random_engine rand_eng;
+    std::normal_distribution<double> normal_std(0.0, 1.0);
+
+    auto rd = normal_std(rand_eng);
+    std::cout << "random double = " << rd << std::endl;
+
+    double dsum(0.0);
+    for (size_t i = 0; i < 10000000; i++)
+    {
+        dsum += normal_std(rand_eng);
+    }
+    end = std::chrono::steady_clock::now();
+    span = end - start;
+    std::cout << "time span in seconds: " << span.count() << std::endl;
+    std::cout << "dsum = " << dsum << std::endl;
+
+
+    start = std::chrono::steady_clock::now();
+    std::default_random_engine rand_eng1;
+
+    double dsum2(0.0);
+    for (size_t i = 0; i < 10000000; i++)
+    {
+        std::normal_distribution<double> normal_std(0.0, 1.0);
+        dsum2 += normal_std(rand_eng1);
+    }
+    end = std::chrono::steady_clock::now();
+    span = end - start;
+    std::cout << "time span in seconds: " << span.count() << std::endl;
+    std::cout << "dsum2 = " << dsum2 << std::endl;
+
+    return EXIT_SUCCESS;
+}