Compilare: main.cpp: In function 'bool check(int)': main.cpp:17:23: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 17 | if(x.length() < val) | ~~~~~~~~~~~^~~~~ main.cpp:22:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 22 | for(int i = 0; i < x.length() - val + 1; ++ i) | ~~^~~~~~~~~~~~~~~~~~~~~~