Compilare: user.cpp: In function ‘long long int termen()’: user.cpp:38:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (epos < E[eind].size() && E[eind][epos] == '*') { ^ user.cpp: In function ‘long long int expr()’: user.cpp:47:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (epos < E[eind].size() && (E[eind][epos] == '-' || E[eind][epos] == '+')) { ^ user.cpp: In function ‘int main()’: user.cpp:122:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 2 ; i < S.size() ; ++i) ^ user.cpp:140:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( ; ps < S.size() ; ++ps) ^