Compilare: user.cpp: In function ‘int main()’: user.cpp:100:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (pos < ev_T.size()) { ^ user.cpp:77:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arcas.in","r",stdin); ^ user.cpp:78:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arcas.out","w",stdout); ^ user.cpp:80:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp: In member function ‘void target::read()’: user.cpp:22:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &x, &y1, &y2); ^ user.cpp: In member function ‘void arrow::read()’: user.cpp:35:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &x1, &y, &x2); ^