Compilare: user.cpp: In member function ‘void bigNR::operator*=(int)’: user.cpp:29:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<val.size();i++){ ~^~~~~~~~~~~ user.cpp: In member function ‘void bigNR::operator+=(const bigNR&)’: user.cpp:42:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<max(oth.val.size(),val.size());i++){ ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ user.cpp:43:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] t += (i < val.size() ? val[i] : 0) + (i < oth.val.size() ? oth.val[i] : 0); ~~^~~~~~~~~~~~ user.cpp:43:53: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] t += (i < val.size() ? val[i] : 0) + (i < oth.val.size() ? oth.val[i] : 0); ~~^~~~~~~~~~~~~~~~ user.cpp:44:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (i >= val.size()) val.push_back(0); ~~^~~~~~~~~~~~~ user.cpp:49:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (i >= val.size()) val.push_back(0); ~~^~~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:75:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("tperm.in","r",stdin); ^ user.cpp:76:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("tperm.out","w",stdout); ^