Compilare: main.cpp: In function 'void insert(std::string)': main.cpp:13:18: 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(int i=0;i<s.size();++i){ | ~^~~~~~~~~ main.cpp: In function 'void erase(std::string)': main.cpp:26:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 26 | for(int i=0;i<s.size();++i){ | ~^~~~~~~~~ main.cpp:32:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 32 | for(int i=0;i<s.size();++i){ | ~^~~~~~~~~ main.cpp: In function 'int count(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(int i=0;i<s.size();++i){ | ~^~~~~~~~~ main.cpp: In function 'int pref(std::string)': main.cpp:52:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 52 | for(int i=0;i<s.size();++i){ | ~^~~~~~~~~