Compilare: main.cpp: In function 'int main()': main.cpp:11:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 11 | for(int i=0; i<e.size(); i++) | ~^~~~~~~~~ main.cpp:22:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 22 | while(i<e.size() && e[i]>='0' && e[i]<='9') | ~^~~~~~~~~