error checking for Grid

2020/03.cpp

@@ -22,11 +22,12 @@ namespace {
 
 auto Ski(Grid const& grid, Coord step) -> std::size_t
 {
-  std::size_t const w = grid.rows[0].size();
+  std::size_t const w = grid.Cols();
+  std::size_t const h = grid.Rows();
   std::size_t trees {0};
   Coord here {0,0};
 
-  while(here.y < grid.rows.size()) {
+  while(here.y < h) {
     if (grid[here] == '#') trees++;
     here += step;
     while (here.x >= w) { here.x -= w; }