Initial set-up for 2019 AoC.

2019/src/runner.cpp

@@ -0,0 +1,34 @@
+#include "solutions.hpp"
+#include <iostream>
+#include <charconv>
+#include <cstring>
+
+template<typename Int, int Radix = 10>
+Int int_from_cstr(Int &value, const char *begin) {
+    const char *end = begin + std::strlen(begin);
+    auto result = std::from_chars(begin, end, value, Radix);
+    if (result.ec != std::errc()) {
+        throw std::invalid_argument("Unparseable integer");
+    }
+
+    return value;
+}
+
+int main(int argc, const char *argv[]) {
+    if (argc < 2) {
+        std::cerr << "Specify a day to run.\n";
+        return 1;
+    }
+
+    int day;
+    int_from_cstr(day, argv[1]);
+
+    const aoc2019::solution_t solution = aoc2019::get_implementation(day);
+    if (solution != nullptr) {
+        solution(std::cin, std::cout);
+        return 0;
+    } else {
+        std::cerr << "Unimplemented.\n";
+        return 1;
+    }
+}