Compilare: main.cpp: In function 'int main()': main.cpp:13:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 13 | for(i=0; i<st.size(); i++) | ~^~~~~~~~~~ main.cpp:10:9: warning: unused variable 'n' [-Wunused-variable] 10 | int n, a, i, cnt=0; | ^ main.cpp:10:12: warning: unused variable 'a' [-Wunused-variable] 10 | int n, a, i, cnt=0; | ^