Compilare: user.cpp: In function ‘int main()’: user.cpp:70:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 1;k < vec.size();++k) ^ user.cpp:31:17: warning: unused variable ‘nr’ [-Wunused-variable] int j = 0,k=0,nr=0,el=0,e=0; ^ user.cpp:31:22: warning: unused variable ‘el’ [-Wunused-variable] int j = 0,k=0,nr=0,el=0,e=0; ^ user.cpp:31:27: warning: unused variable ‘e’ [-Wunused-variable] int j = 0,k=0,nr=0,el=0,e=0; ^