Compilare: main.cpp: In function 'int countnum(std::string)': main.cpp:12:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 12 | for(i = 0; i < n.length(); ++i) { | ~~^~~~~~~~~~~~ main.cpp: In function 'int countnum2(std::string)': main.cpp:42:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 42 | for(i = 0; i < n.length(); ++i) { | ~~^~~~~~~~~~~~ main.cpp:39:12: warning: variable 'cnt' set but not used [-Wunused-but-set-variable] 39 | int i, cnt; | ^~~ main.cpp: In function 'int main()': main.cpp:69:15: warning: unused variable 'cnt' [-Wunused-variable] 69 | int task, cnt, i; | ^~~ main.cpp:69:20: warning: unused variable 'i' [-Wunused-variable] 69 | int task, cnt, i; | ^