Compilare: main.cpp: In function 'bool done()': main.cpp:31:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 31 | for (int i = 1; i < fi.size(); i++) { | ~~^~~~~~~~~~~ main.cpp:49:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 49 | for (int i = 1; i < en.size(); i++) { | ~~^~~~~~~~~~~ main.cpp:64:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 64 | for (int i = 0; i < chars.size(); i++) { | ~~^~~~~~~~~~~~~~ main.cpp:15:12: warning: control reaches end of non-void function [-Wreturn-type] 15 | string fi; | ^~