Compilare: main.cpp: In function 'int main()': main.cpp:32:19: 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=1; i<a.size(); i++) | ~^~~~~~~~~ main.cpp:37:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 37 | for(int i=1; i<b.size(); i++) | ~^~~~~~~~~ main.cpp:44:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 44 | for(int i=1; i<=b.size(); i++) | ~^~~~~~~~~~ main.cpp:52:11: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else] 52 | if(hash_substr(i,i+a.size()-2)==hash_a) | ^