Compilare: main.cpp: In function 'bool ok(std::__cxx11::string, std::__cxx11::string)': main.cpp:32:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i <= a.size(); i++) { ~~^~~~~~~~~~~ main.cpp:33:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j <= b.size(); j++) ~~^~~~~~~~~~~ main.cpp:36:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i <= b.size(); i++) ~~^~~~~~~~~~~ main.cpp:38:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i <= a.size(); i++) ~~^~~~~~~~~~~