Compilare: user.cpp: In member function ‘void T::join(std::vector<int>&, std::vector<int>&, std::vector<int>&)’: user.cpp:52:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < l.size() && j < r.size()) { ^ user.cpp:52:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < l.size() && j < r.size()) { ^ user.cpp:59:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < l.size()) { ^ user.cpp:62:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j < r.size()) { ^ user.cpp: In function ‘int main()’: user.cpp:231:29: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d %d", &N, &M); ^ user.cpp:233:31: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d %d", &u, &v); ^ user.cpp:239:29: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d", &val[u]); ^ user.cpp:247:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("viteza.out", "w", stdout); ^ user.cpp:249:38: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d %d %d", &u, &v, &k); ^