Compilare: user.cpp: In function ‘int main()’: user.cpp:25:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<dif.size();i++){ ^ user.cpp:9:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sort.in","r",stdin); ^ user.cpp:10:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sort.out","w",stdout); ^ user.cpp:12:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:15:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&a[i]); ^