Part one of day 2, 2022, but I don't have time to finish this at the moment.

2022/2/main.cpp

@@ -0,0 +1,88 @@
+#include <fstream>
+#include <iostream>
+#include <string>
+
+enum RPS {
+	Rock = 1,
+	Paper,
+	Scissors,
+};
+
+RPS ToRPS(char c)
+{
+	if(c == 'A' || c == 'X')
+		return RPS::Rock;
+	else if(c == 'B' || c == 'Y')
+		return RPS::Paper;
+	else if(c == 'C' || c == 'Z')
+		return RPS::Scissors;
+
+	std::cerr << "BAD DATA '" << c << "'." << std::endl;
+	exit(-1);
+}
+
+int RPSScore(RPS rps)
+{
+	switch(rps)
+	{
+	case RPS::Rock:
+		return 1;
+	case RPS::Paper:
+		return 2;
+	case RPS::Scissors:
+		return 3;
+	}
+}
+
+bool Won(RPS us, RPS them)
+{
+	if(us == RPS::Rock && them == RPS::Scissors)
+		return true;
+	else if(us == RPS::Paper && them == RPS::Rock)
+		return true;
+	else if(us == RPS::Scissors && them == RPS::Paper)
+		return true;
+
+	return false;
+}
+
+int Points(RPS us, RPS them)
+{
+	int rtn = 0;
+
+	// score our play:
+	rtn += RPSScore(us);
+
+	// tie:
+	if(us == them)
+		return rtn + 3;
+	// win:
+	if(Won(us, them))
+		return rtn + 6;
+	// loss:
+	return rtn;
+}
+
+int main()
+{
+	std::ifstream ifs("data.txt");
+	if(!ifs.is_open())
+	{
+		std::cerr << "Missing data.txt." << std::endl;
+		return -1;
+	}
+
+	unsigned long total = 0;
+
+	for(std::string line; std::getline(ifs, line); )
+	{
+		char them = line[0];
+		char us = line[2];
+
+		total += Points(ToRPS(us), ToRPS(them));
+	}
+
+	std::cout << "Total: " << total << std::endl;
+
+	return 0;
+}