Compilare: user.cpp: In function ‘std::string termen()’: user.cpp:17:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (p == S.length()) ^ user.cpp:24:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (p < S.length() && S[p] >= 'A' && S[p] <= 'Z') { ^ user.cpp: In function ‘bool factor()’: user.cpp:88:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (p < S.length() && S[p] == ' ' || S[p] == ')') ^ user.cpp:88:27: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] while (p < S.length() && S[p] == ' ' || S[p] == ')') ^ user.cpp: In function ‘bool not_eval()’: user.cpp:67:12: warning: ‘r’ may be used uninitialized in this function [-Wmaybe-uninitialized] return r; ^