Compilare: user.cpp: In function ‘void read()’: user.cpp:54:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("concert2.in", "r", stdin); ^ user.cpp:55:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &n, &k1, &k2); ^ user.cpp:59:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &v[i].x); ^ user.cpp: In function ‘void write()’: user.cpp:113:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("concert2.out", "w", stdout); ^