Compilare: user.cpp: In function ‘int main()’: user.cpp:20:38: warning: ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second: [enabled by default] fin.seekg (fin.tellg() + 1); ^ In file included from /usr/include/c++/4.8/iosfwd:40:0, from /usr/include/c++/4.8/ios:38, from /usr/include/c++/4.8/istream:38, from /usr/include/c++/4.8/fstream:38, from user.cpp:1: /usr/include/c++/4.8/bits/postypes.h:178:7: note: candidate 1: std::fpos<_StateT> std::fpos<_StateT>::operator+(std::streamoff) const [with _StateT = __mbstate_t; std::streamoff = long long int] operator+(streamoff __off) const ^ user.cpp:20:38: note: candidate 2: operator+(std::streamoff {aka long long int}, int) <built-in> fin.seekg (fin.tellg() + 1); ^