Compilare: user.cpp: In function ‘int main()’: user.cpp:65:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; s[j] != '.' && j < s.size(); j++) ^ user.cpp:69:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 1; k <= 6 && j < s.size(); k++, j++) ^ user.cpp:77:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; s[j] != '.' && j < s.size(); j++) ^ user.cpp:81:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 1; k <= 6 && j < s.size(); k++, j++) ^