Compilare: main.cpp: In function 'double parseNumber(const std::string&)': main.cpp:15:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 15 | while (i < s.size() && std::isdigit(s[i])) { | ~~^~~~~~~~~~ main.cpp:18:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 18 | if (i < s.size() && s[i] == '.') { | ~~^~~~~~~~~~ main.cpp:21:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 21 | while (i < s.size() && std::isdigit(s[i])) { | ~~^~~~~~~~~~ main.cpp: In function 'double parseFactor(const std::string&)': main.cpp:30:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 30 | if (i < s.size() && s[i] == '-') { | ~~^~~~~~~~~~ main.cpp:34:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 34 | if (i < s.size() && s[i] == '+') { | ~~^~~~~~~~~~ main.cpp:38:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 38 | if (i < s.size() && s[i] == '(') { | ~~^~~~~~~~~~ main.cpp:41:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 41 | if (i < s.size() && s[i] == ')') { | ~~^~~~~~~~~~ main.cpp: In function 'double parseTerm(const std::string&)': main.cpp:51:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 51 | while (i < s.size() && (s[i] == '*' || s[i] == '/')) { | ~~^~~~~~~~~~ main.cpp: In function 'double parseExpression(const std::string&)': main.cpp:62:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 62 | while (i < s.size() && (s[i] == '+' || s[i] == '-')) { | ~~^~~~~~~~~~