Compilare: user.cpp: In function ‘int main()’: user.cpp:17:28: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(in, "r", stdin); ^ user.cpp:18:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(out, "w", stdout); ^ user.cpp:19:34: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(a + 1, MAXN + 2, stdin); ^ user.cpp:20:34: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(b + 1, MAXN + 2, stdin); ^