Compilare: user.cpp: In function ‘void read()’: user.cpp:82:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("namlei.in", "r", stdin); ^ user.cpp:83:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("namlei.out", "w", stdout); ^ user.cpp:84:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d", &N, &K, &X, &Y); ^ user.cpp:91:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &cnt, &j, &k); ^ user.cpp: In function ‘void solve()’: user.cpp:113:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d", &i, &x, &j, &y); ^