Compilare: user.cpp: In function ‘int countLetter(std::__cxx11::string)’: user.cpp:41:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < text.length(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:67:17: warning: ignoring return value of ‘int system(const char*)’, declared with attribute warn_unused_result [-Wunused-result] system("pause"); ^