Compilare: user.cpp: In function ‘int main()’: user.cpp:37:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(p < s.size() && s[p] >= '0' && s[p] <= '9') ^ user.cpp:41:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(p < s.size() && s[p] >= '0' && s[p] <= '9') ^