Compilare: main.cpp: In function 'int main()': main.cpp:48:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 48 | while(pos < s.size()) | ~~~~^~~~~~~~~~ main.cpp:50:13: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 50 | while(pos < s.size() && s[pos] == ')') | ~~~~^~~~~~~~~~