Pseudo-random numbers/Combined recursive generator MRG32k3a: Difference between revisions

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     for (i = 0; i < 5; i++) {
         printf("%d: %d\n", i, counts[i]);
+    }
+    return 0;
+}</lang>
+{{out}}
+<pre>1459213977
+2827710106
+4245671317
+3877608661
+2595287583
+: 20002
+: 20060
+: 19948
+: 20059
+: 19931</pre>
+=={{header|C++}}==
+{{trans|C}}
+<lang cpp>#include <array>
+#include <iostream>
+int64_t mod(int64_t x, int64_t y) {
+    int64_t m = x % y;
+    if (m < 0) {
+        if (y < 0) {
+            return m - y;
+        } else {
+            return m + y;
+        }
+    }
+    return m;
+}
+class RNG {
+private:
+    // First generator
+    const std::array<int64_t, 3> a1{ 0, 1403580, -810728 };
+    const int64_t m1 = (1LL << 32) - 209;
+    std::array<int64_t, 3> x1;
+    // Second generator
+    const std::array<int64_t, 3> a2{ 527612, 0, -1370589 };
+    const int64_t m2 = (1LL << 32) - 22853;
+    std::array<int64_t, 3> x2;
+    // other
+    const int64_t d = (1LL << 32) - 209 + 1; // m1 + 1
+public:
+    void seed(int64_t state) {
+        x1 = { state, 0, 0 };
+        x2 = { state, 0, 0 };
+    }
+    int64_t next_int() {
+        int64_t x1i = mod((a1[0] * x1[0] + a1[1] * x1[1] + a1[2] * x1[2]), m1);
+        int64_t x2i = mod((a2[0] * x2[0] + a2[1] * x2[1] + a2[2] * x2[2]), m2);
+        int64_t z = mod(x1i - x2i, m1);
+        // keep last three values of the first generator
+        x1 = { x1i, x1[0], x1[1] };
+        // keep last three values of the second generator
+        x2 = { x2i, x2[0], x2[1] };
+        return z + 1;
+    }
+    double next_float() {
+        return static_cast<double>(next_int()) / d;
+    }
+};
+int main() {
+    RNG rng;
+    rng.seed(1234567);
+    std::cout << rng.next_int() << '\n';
+    std::cout << rng.next_int() << '\n';
+    std::cout << rng.next_int() << '\n';
+    std::cout << rng.next_int() << '\n';
+    std::cout << rng.next_int() << '\n';
+    std::cout << '\n';
+    std::array<int, 5> counts{ 0, 0, 0, 0, 0 };
+    rng.seed(987654321);
+    for (size_t i = 0; i < 100000; i++) 		{
+        auto value = floor(rng.next_float() * 5.0);
+        counts[value]++;
+    }
+    for (size_t i = 0; i < counts.size(); i++) 		{
+        std::cout << i << ": " << counts[i] << '\n';
     }