Compilare: main.cpp: In function 'long long int fact()': main.cpp:26:18: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 26 | while (i < s.size() && s[i] >= '0' && s[i] <= '9') { | ~~^~~~~~~~~~ main.cpp: In function 'long long int term()': main.cpp:35:18: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 35 | while (i < s.size() && (s[i] == '*' || s[i] == '/')) { | ~~^~~~~~~~~~ main.cpp: In function 'long long int eval()': main.cpp:50:18: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 50 | while (i < s.size() && (s[i] == '+' || s[i] == '-')) { | ~~^~~~~~~~~~