Compilare: main.cpp: In function 'int main()': main.cpp:109:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 109 | for(i = 0; i < r.length(); i ++) | ~~^~~~~~~~~~~~ main.cpp:88:7: warning: unused variable 'n' [-Wunused-variable] 88 | int n, i; | ^