Compilare: user.cpp: In function ‘int main()’: user.cpp:7:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("grad.in","r",stdin) ; ^ user.cpp:8:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("grad.out","w",stdout) ; ^ user.cpp:32:46: warning: iteration 25u invokes undefined behavior [-Waggressive-loop-optimizations] for(i = 1 ; i <= 26 ; ++ i) f[i] = 0 ; ^ user.cpp:32:23: note: containing loop for(i = 1 ; i <= 26 ; ++ i) f[i] = 0 ; ^ user.cpp:28:24: warning: iteration 25u invokes undefined behavior [-Waggressive-loop-optimizations] grad *= f[i] + 1 ; ^ user.cpp:27:23: note: containing loop for(i = 1 ; i <= 26 ; ++ i){ ^