Compilare: user.cpp: In function ‘int evalueaza()’: user.cpp:29:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (pos<str.size() && (str[pos] == '+' || str[pos] == '-')) ^ user.cpp: In function ‘int termen()’: user.cpp:52:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (pos<str.size() && (str[pos] == '*' || str[pos] == '/')) ^ user.cpp: In function ‘int factor()’: user.cpp:82:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (pos<str.size() && '0' <= str[pos] && str[pos] <= '9') ^