Add BitField.h

Author: franekwitt

content/various/BitField.h

@@ -0,0 +1,25 @@
+/**
+ * Author:
+ * License: CC0
+ * Source: Own work
+ * Description: Pack many custom size "variables" into one using bitfields.
+ * WARNING: It is not possible to take references to such "variables".
+ * Overflow on such "variables" (even an unsigned ones) is implementation defined.
+ */
+
+#include<bits/stdc++.h>
+using namespace std;
+
+struct X {
+    unsigned a: 10, b: 12, c: 10;
+};
+
+static_assert(sizeof(X) == 4);
+
+int main() {
+    X s;
+    s.a = 0;
+    s.b = 10;
+    s.c = 20;
+    cout << s.a << " " << s.b << " " << s.c << endl;
+}