Compilare: user.cpp: In function ‘int main()’: user.cpp:32:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < v[z].size(); i++) ^ user.cpp:53:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < v[z].size(); i++) ^ user.cpp:45:14: warning: ‘z’ may be used uninitialized in this function [-Wmaybe-uninitialized] viz[s] =1; ^