Compilare: user.cpp: In function ‘void solve()’: user.cpp:178:39: warning: operation on ‘N’ may be undefined [-Wsequence-point] V[++ N].x = V[N - 1].y; ^ user.cpp: In function ‘void read()’: user.cpp:109:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("culoar.in", "r", stdin); ^ user.cpp:111:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:114:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &v[i].x, &v[i].y); ^ user.cpp: In function ‘void write()’: user.cpp:195:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("culoar.out", "w", stdout); ^