Compilare: user.cpp: In function ‘int main()’: user.cpp:22:13: warning: unused variable ‘j’ [-Wunused-variable] long i, j; ^ user.cpp:24:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("perfect2.in", "r", stdin); ^ user.cpp:25:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("perfect2.out", "w", stdout); ^ user.cpp:26:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld %ld", &p, &n); ^ user.cpp:29:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld %ld", &x, &y); ^