Compilare: main.cpp: In function 'std::string build_invers(std::string)': main.cpp:19:32: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 19 | for(int indice = 0; indice < original.size(); indice++) | ~~~~~~~^~~~~~~~~~~~~~~~~