Compilare: user.cpp: In function ‘bool T2()’: user.cpp:36:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (pos < E[e].size() && E[e][pos] == '&') { ^ user.cpp: In function ‘bool T1()’: user.cpp:45:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (pos < E[e].size() && E[e][pos] == '^') { ^ user.cpp: In function ‘bool expr()’: user.cpp:54:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (pos < E[e].size() && E[e][pos] == '|') { ^ user.cpp: In function ‘std::string eval()’: user.cpp:92:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0 ; i < E[j].size() ; ++i) ^