Implement random in 5 ways

practice/main.cc

@@ -0,0 +1,74 @@
+#include <iostream>
+#include <cstdlib>
+#include <cstdio>
+#include <immintrin.h>
+#include <vector>
+#include <sys/random.h>
+#include <ctime>
+
+using namespace std;
+
+int get_random_std()
+{
+    return rand() % 200;
+}
+
+int get_random_rdrand()
+{
+    unsigned int ret;
+    int rc = _rdrand32_step(&ret);
+    if (rc == 1) return ret;
+    return -1;
+}
+
+int get_random_dev_urandom()
+{
+    int ret, read;
+    FILE *urandom = fopen("/dev/urandom", "r");
+    read = fread(&ret, sizeof(ret), 1, urandom);
+    fclose(urandom);
+    if (read > 0) return ret;
+    return -1;
+}
+
+int get_random_getrandom()
+{
+    int ret, read;
+    read = getrandom(&ret, sizeof(ret), 0);
+    if (read > 0) return ret;
+    return read;
+}
+
+int get_random(int (*random_func)())
+{
+    return random_func() % 200;
+}
+
+typedef int (*fp)();
+
+int main()
+{
+    int n;
+    cout << "Please enter a number" << endl;
+    cin >> n;
+
+    srand((unsigned) time(NULL));
+
+    vector<fp> randoms = {
+        get_random_getrandom,
+        get_random_dev_urandom,
+        get_random_rdrand,
+        get_random_std
+    };
+
+    for (int i = 0; i < 5; i++)
+    {
+        if (get_random(randoms[i % 4]) == 150)
+            n += 1;
+        else
+            i--;
+    }
+
+    cout << "Your number + 5 is: " << n << endl;
+    return 0;
+}