Compilare: main.cpp: In function 'void calc()': main.cpp:67:29: warning: suggest parentheses around '&&' within '||' [-Wparentheses] polo.top() = (polo.top() && !x || !polo.top() && x); ~~~~~~~~~~~^~~~~ main.cpp: In function 'bool rez(std::__cxx11::string)': main.cpp:76:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < s.length(); ++i) ~~^~~~~~~~~~~~ main.cpp: In function 'void backt(int)': main.cpp:104:8: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (p < var.size()) ~~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:129:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < e1.length(); ++j) ~~^~~~~~~~~~~~~ main.cpp:132:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < e2.length(); ++j) ~~^~~~~~~~~~~~~ main.cpp: In function 'bool valoare(char)': main.cpp:30:35: warning: 'mij' may be used uninitialized in this function [-Wmaybe-uninitialized] int st = 0, dr = var.size() - 1, mij; ^~~