Compilare: main.cpp: In function 'bool OR()': main.cpp:37:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (s.substr(i, 2) == "OR" && i + 1 < s.size()) { ~~~~~~^~~~~~~~~~ main.cpp: In function 'bool AND()': main.cpp:46:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (s.substr(i, 3) == "AND" && i + 2 < s.size()) { ~~~~~~^~~~~~~~~~ main.cpp: In function 'bool NOT()': main.cpp:55:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (s.substr(i, 3) == " NOT " && i + 2 < s.size()) { ~~~~~~^~~~~~~~~~ main.cpp: In function 'bool op()': main.cpp:69:50: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] } else if (s.substr(i, 4) == "TRUE" && i + 3 < s.size()) { ~~~~~~^~~~~~~~~~ main.cpp:72:52: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] } else if (s.substr(i , 5) == "FALSE" && i + 4 < s.size()) { ~~~~~~^~~~~~~~~~ main.cpp:76:21: warning: array subscript has type 'char' [-Wchar-subscripts] rez = v[s[i]]; ^ main.cpp: In function 'int main()': main.cpp:89:12: warning: array subscript has type 'char' [-Wchar-subscripts] v[c] = !v[c]; ^ main.cpp:89:20: warning: array subscript has type 'char' [-Wchar-subscripts] v[c] = !v[c]; ^