Compilare: user.cpp: In function ‘int main()’: user.cpp:95:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<v.size();++i){ ^ user.cpp:96:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i<v.size()-1&&v[i+1].first==v[i].first)++i; ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:34:51: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:12:47: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^