Compilare: main.cpp: In function 'bool check_and(std::__cxx11::string&)': main.cpp:20:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (p >= s.length()) ~~^~~~~~~~~~~~~ main.cpp:24:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] return p+2 < s.length() && s[p] == 'A' && s[p+1] == 'N' && s[p+2] == 'D'; ~~~~^~~~~~~~~~~~ main.cpp: In function 'bool check_or(std::__cxx11::string&)': main.cpp:29:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (p >= s.length()) ~~^~~~~~~~~~~~~ main.cpp:33:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] return p+1 < s.length() && s[p] == 'O' && s[p+1] == 'R'; ~~~~^~~~~~~~~~~~ main.cpp: In function 'bool element(std::__cxx11::string&)': main.cpp:69:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (p+2 < s.length() && s[p] == 'N' && s[p+1] == 'O' && s[p+2] == 'T'){ ~~~~^~~~~~~~~~~~ main.cpp:78:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] }else if (p+3 < s.length() && s[p] == 'T' && s[p+1] == 'R' && s[p+2] == 'U' && s[p+3] == 'E'){ ~~~~^~~~~~~~~~~~ main.cpp:81:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] }else if (p+4 < s.length() && s[p] == 'F' && s[p+1] == 'A' && s[p+2] == 'L' && s[p+3] == 'S' && s[p+4] == 'E'){ ~~~~^~~~~~~~~~~~ main.cpp:86:25: warning: array subscript has type 'char' [-Wchar-subscripts] ret = val[s[p-1]]; ^ main.cpp: In function 'int main()': main.cpp:102:14: warning: array subscript has type 'char' [-Wchar-subscripts] val[q] ^= 1; ^