Compilare: user.cpp: In function ‘void read()’: user.cpp:25:9: warning: unused variable ‘x’ [-Wunused-variable] int x, y; ^ user.cpp:25:12: warning: unused variable ‘y’ [-Wunused-variable] int x, y; ^ user.cpp: In function ‘void solve()’: user.cpp:47:9: warning: unused variable ‘j’ [-Wunused-variable] int j, x, y, mx = 0; ^ user.cpp:47:15: warning: unused variable ‘y’ [-Wunused-variable] int j, x, y, mx = 0; ^ user.cpp: In function ‘void read()’: user.cpp:26:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cover.in", "r", stdin); ^ user.cpp:27:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &l); ^ user.cpp:29:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &cost[i]); ^ user.cpp:32:41: 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:75:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cover.out", "w", stdout); ^