Compilare: user.cpp: In function ‘int main()’: user.cpp:15:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<x.size();i++) ^ user.cpp:20:22: warning: value computed is not used [-Wunused-value] fout<<i+1<" "; ^ user.cpp:11:13: warning: unused variable ‘n’ [-Wunused-variable] int i,j,n; ^