Fix MSVC Warnings

demo/env.h

@@ -9,12 +9,12 @@ namespace env {
 
 std::optional<std::string> get(char const *sv) {
 #ifdef _WIN32
-  char *s;
-  size_t n;
+  char *s{};
+  size_t n{};
   // On Windows, _dupenv_s is the Microsoft-recommended way of reading an
   // environment variable. When the variable isn't found, the error (e) is 0 and
   // the count (n) is also 0 (also, the buffer [s] is set to NULL).
-  if (auto e = _dupenv_s(&s, &n, sv); e || !n)
+  if (auto e = _dupenv_s(&s, &n, sv); e || !s)
     return {};
   std::string t{s, n};
   // According to Microsoft, the buffer s must be freed using a call to `free`.

demo/main.cpp

@@ -2,7 +2,6 @@
 #include <cmath>
 #include <complex>
 #include <cstdlib>
-#include <halton.h>
 #include <random>
 #include <raylib.h>
 #include <stdexcept>
@@ -15,9 +14,13 @@
 #include "Table.h"
 #include "env.h"
 #include "user.h"
+#include <numbers>
+#include <utility>
 
 using namespace phy;
 
+namespace main_program {
+
 /// Constants controlling the program.
 struct Constants {
   /// Inclusive upper limit of the number of particles.
@@ -211,7 +214,7 @@ struct State {
     EndDrawing();
   }
 
-  User make_user() {
+  User make_user() const {
     User u;
     if (constants.flags.galaxies)
       u.control.demo = false;
@@ -222,10 +225,13 @@ struct State {
     return constants.flags.galaxies ? galaxies(constants) : figure8();
   }
 } state;
+} // namespace main_program
 
-void do_loop() { state.loop(); }
+void do_loop() { main_program::state.loop(); }
 
 static int do_main() {
+  using namespace main_program;
+
   SetConfigFlags(FLAG_WINDOW_RESIZABLE);
   InitWindow(600, 600, "Grass Gravity Simulation");