Compilare: user.cpp: In function ‘bool Ok(int, int)’: user.cpp:70:18: warning: the address of ‘w’ will always evaluate as ‘true’ [-Waddress] if (!w) ^ user.cpp: In function ‘void read()’: user.cpp:23:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("patrate.in", "r", stdin); ^ user.cpp:24:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:28:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%u %u", &v[i].x, &v[i].y); ^ user.cpp: In function ‘void write()’: user.cpp:109:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("patrate.out","w", stdout); ^