Compilare: user.cpp: In function ‘bool count(const point&)’: user.cpp:109:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < points.size(); ++ i) ^ user.cpp: In function ‘std::vector<point> convex_hull(std::vector<point>&)’: user.cpp:137:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < points.size(); ++ i) ^ user.cpp:152:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 2; i < points.size(); ++ i) { ^ user.cpp: In function ‘std::vector<point> add_middles(const std::vector<point>&)’: user.cpp:168:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < points.size() - 1; ++ i) { ^ user.cpp: In function ‘std::vector<line> get_possible_axes(const std::vector<point>&)’: user.cpp:192:64: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0, j = points.size() / 2; i < points.size() / 2; ++ i, ++ j) ^ user.cpp: In function ‘bool is_axis(const line&)’: user.cpp:199:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < points.size(); ++ i) ^