Compilare: user.cpp: In function ‘void rec(int, std::string, int)’: user.cpp:15:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(s.size()>x || ok==1)return; ^ user.cpp:16:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(isdigit(s[i]) && i<s.size() && a[i]==s[i])i++; ^ user.cpp:17:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(isdigit(s[i]) && i<s.size() && a[i]!=s[i])return ; ^ user.cpp:18:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i==s.size()) ^ user.cpp:20:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(s.size()==x)ok=1; ^ user.cpp: In function ‘int main()’: user.cpp:42:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<s.size();j++) ^