Compilare: user.cpp: In function ‘int main()’: user.cpp:47:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j, x, y; ^ user.cpp:45:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("marmote.in", "r", stdin); ^ user.cpp:46:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("marmote.out", "w", stdout); ^ user.cpp:49:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &n, &m, &k, &lim); ^ user.cpp:51:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^