Compilare: main.cpp: In function 'int factor(int&, std::string&)': main.cpp:13:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 13 | while(i<str.size() and str[i]>='0' and str[i]<='9') | ~^~~~~~~~~~~ main.cpp: In function 'int evaluate(std::string)': main.cpp:31:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 31 | for(int i=0;i<str.size();i++) | ~^~~~~~~~~~~