Compilare: user.cpp: In function ‘int main()’: user.cpp:64:8: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] si[i+1]=NULL; ^ user.cpp:5:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("culori3.in","r",stdin); ^ user.cpp:6:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("culori3.out","w",stdout); ^ user.cpp:9:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^