Compilare: user.cpp: In function ‘int main()’: user.cpp:20:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s.size(); i += 8, k++) ~~^~~~~~~~~~ user.cpp:57:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < message.size(); ++i) { ~~^~~~~~~~~~~~~~~~ user.cpp:64:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < wrongChars.size(); ++i) ~~^~~~~~~~~~~~~~~~~~~