Game itself is functional and correct

Makefile

@@ -0,0 +1,11 @@
+CXX = g++
+CXXFLAGS = -Wall
+
+gol: main.o
+	$(CXX) $(CXXFLAGS) -o gol main.o
+
+main.o: main.cpp
+	$(CXX) $(CXXFLAGS) -c main.cpp
+
+clean :
+	-rm *.o gol

main.cpp

@@ -0,0 +1,156 @@
+#include <iostream>
+#include <fstream>
+#include <climits>
+#include <vector>
+#include <map>
+#include <algorithm>
+
+#define LIVE_CELL 'x'
+#define DEAD_CELL '.'
+
+struct World {
+    World(int size_x, int size_y) : size_x(size_x), size_y(size_y) {
+        data = new char*[size_y];
+
+        for (int y = 0; y < size_y; y++) {
+            data[y] = new char[size_x];
+        }
+    }
+
+    ~World() {
+        for (int y = 0; y < size_y; y++) {
+            delete data[y];
+        }
+        
+        delete data;
+    }
+
+    char **data;
+    
+    char get_value(int x, int y) {
+        if (x < 0) x += size_x;
+        if (y < 0) y += size_y;
+        if (x >= size_x) x -= size_x;
+        if (y >= size_y) y -= size_y;
+        return data[y][x];
+    }
+
+    void set_alive(int x, int y) {
+        data[y][x] = LIVE_CELL;
+    }
+
+    void set_dead(int x, int y) {
+        data[y][x] = DEAD_CELL;
+    }
+
+    void set(int x, int y, char val) {
+        data[y][x] = val;
+    }
+
+    int size_x;
+    int size_y;
+};
+
+void generation(World &world) {
+    // Set neighbor counts
+    int **neighbor_counts = new int*[world.size_y];
+    for (int y = 0; y < world.size_y; y++) {
+        neighbor_counts[y] = new int[world.size_x];
+    }
+
+    for (int y = 0; y < world.size_y; y++) {
+        for (int x = 0; x < world.size_x; x++) {
+            // Get number of living neighbors
+            int neighbors = 0;
+
+            for (int local_y = -1; local_y < 2; local_y++) {
+                for (int local_x = -1; local_x < 2; local_x++) {
+                    // Ignore self
+                    if (local_x == 0 && local_y == 0) continue;
+
+                    if (world.get_value(x + local_x, y + local_y) == LIVE_CELL) {
+                        neighbors++;
+                    }
+                }
+            }
+
+            neighbor_counts[y][x] = neighbors;
+        }
+    }
+
+    // Update cells accordingly
+    for (int y = 0; y < world.size_y; y++) {
+        for (int x = 0; x < world.size_x; x++) {
+            char this_cell = world.get_value(x, y);
+            int neighbors = neighbor_counts[y][x];
+
+            if (this_cell == DEAD_CELL) {
+                if (neighbors == 3) {
+                    // Any dead cell with exactly three living neighbors becomes a live cell.
+                    world.set_alive(x, y);
+                }
+            } else {
+                if (neighbors < 2 || neighbors > 3) {
+                    // Any live cell with two or three living neighbors lives.
+                    // Any live cell with fewer than two living neighbors dies.
+                    // Any live cell with more than three living neighbors dies.
+                    world.set_dead(x, y);
+                }
+            }
+        }
+    }
+}
+
+int main() {
+    // Read in the start state
+    std::ifstream world_file;
+    world_file.open("random250_in.gol");
+
+    // Get x and y size
+    std::string x_str, y_str;
+    getline(world_file, x_str, ',');
+    getline(world_file, y_str);
+
+    int size_x = std::stoi(x_str);
+    int size_y = std::stoi(y_str);
+
+    World world(size_x, size_y);
+
+    // Set the data
+    for (int y = 0; y < size_y; y++) {
+        std::string line;
+        getline(world_file, line);
+
+        for (int x = 0; x < size_x; x++) {
+            world.set(x, y, line[x]);
+        }
+    }
+    
+    world_file.close();
+
+    // Do some generations
+    for (int i = 0; i < 250; i++) {
+        generation(world);
+    }
+
+    // Write the result
+    std::ofstream result_file;
+    result_file.open("random250_out.gol");
+
+    result_file << size_x << "," << size_y << '\n';
+    
+    for (int y = 0; y < size_y; y++) {
+        std::string line;
+        getline(world_file, line);
+
+        for (int x = 0; x < size_x; x++) {
+            line += world.get_value(x, y);
+        }
+
+        result_file << line << '\n';
+    }
+
+    result_file.close();
+
+    return 0;
+}