Compilare: main.cpp: In function 'i64 verif(std::__cxx11::string, int)': main.cpp:38:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (val.size() - 1 == sz) { ~~~~~~~~~~~~~~~^~~~~ main.cpp:40:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1 ; i < val.size() ; ++ i) { ~~^~~~~~~~~~~~ main.cpp:61:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1 ; i < val.size() ; ++ i) { ~~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:115:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("cifra4.in", "r", stdin) ; ^ main.cpp:116:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("cifra4.out", "w", stdout) ; ^