Compilare: user.cpp: In function ‘int main()’: user.cpp:65:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<r.size()) ^ user.cpp:67:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<r.size() && r[i]==0) ^ user.cpp:70:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j<r.size() && r[j]!=0) ^