Compilare: user.cpp: In function ‘int main()’: user.cpp:16:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<=s.size()+3; i++) ^ user.cpp:18:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<s.size(); i++) ^ user.cpp:20:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(nr=0, j=i; j<s.size() && j<=k+i-1; j++) ^ user.cpp:34:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<v[i].size(); j++) ^