Compilare: main.cpp: In function 'int main()': main.cpp:7:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("sumfact.in","r",stdin); ^ main.cpp:8:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("sumfact.out","w",stdout); ^ main.cpp:10:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ main.cpp:13:13: warning: iteration 11 invokes undefined behavior [-Waggressive-loop-optimizations] v[i]=1; ~~~~^~ main.cpp:11:15: note: within this loop for(i=1; i<=12; i++) ~^~~~