Compilare: user.cpp: In function ‘int main()’: user.cpp:11:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("k1.in", "r", stdin); ^ user.cpp:12:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("k1.out", "w", stdout); ^ user.cpp:15:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ user.cpp:18:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^ user.cpp:85:17: warning: ‘second’ may be used uninitialized in this function [-Wmaybe-uninitialized] s = first + second; ^