Compilare: user.cpp: In function ‘int main()’: user.cpp:27:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < s.size()) ^ user.cpp:31:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j < nr && i + j < s.size()) ^ user.cpp:16:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("smooth2.in","r",stdin); ^ user.cpp:17:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("smooth2.out","w",stdout); ^