Compilare: main.cpp: In function 'int factor()': main.cpp:20:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 20 | while(poz < s.size() && s[poz] - '0' >= 0 && s[poz] - '0' <= 9){ | ~~~~^~~~~~~~~~ main.cpp: In function 'int termen()': main.cpp:33:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 33 | while(poz < s.size() && (s[poz] == '*' || s[poz] == '/')){ | ~~~~^~~~~~~~~~ main.cpp: In function 'int expresie()': main.cpp:49:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 49 | while(poz < s.size() && (s[poz] == '+' || s[poz] == '-')){ | ~~~~^~~~~~~~~~