Compilare: user.cpp: In function ‘int main()’: user.cpp:57:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < Comp.size(); ++ i) ^ user.cpp:59:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < Comp[i].size(); ++ j) printf("%i ", Comp[i][j]); ^