Compilare: main.cpp: In function 'int main()': main.cpp:35:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 35 | for (int i = 0; i < nr.size(); i++) { | ~~^~~~~~~~~~~ main.cpp:43:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 43 | for (int i = p + 1; i < nr.size(); i++) { | ~~^~~~~~~~~~~ main.cpp:51:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 51 | for (int i = 0; i < nr.size(); i++) { | ~~^~~~~~~~~~~ main.cpp:59:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 59 | for (int i = p + 1; i < nr.size(); i++) { | ~~^~~~~~~~~~~ main.cpp:31:14: warning: unused variable 'ch' [-Wunused-variable] 31 | char ch; | ^~