Compilare: user.cpp: In function ‘int main()’: user.cpp:27:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < text.length(); i++) { ^ user.cpp:30:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( ; i < text.length() && ((text[i] >= 'a' && text[i] <= 'z') || (text[i] >= 'A' && text[i] <= 'Z')); i++) ^ user.cpp:18:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("text.in", "r", stdin); ^ user.cpp:19:37: 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); ^