Compilare: user.cpp: In function ‘int main()’: user.cpp:27:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i ++ < input.size()) { ^ user.cpp:41:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (i == input.size() - 1) { ^ user.cpp:11:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("text.out", "w", stdout); ^