Compilare: main.cpp: In function 'int main()': main.cpp:103:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<lista.size()-1;i++) ~^~~~~~~~~~~~~~~ main.cpp:99:29: warning: unused variable 'minus_v' [-Wunused-variable] int plus_v=lista.back(),minus_v=lista.front(); ^~~~~~~