Compilare: main.cpp: In function 'int main()': main.cpp:84:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<C.size();i++) ~^~~~~~~~~ main.cpp:87:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<C.size();i++) ~^~~~~~~~~ main.cpp:90:18: warning: unused variable 'it' [-Wunused-variable] for(auto it:C[i]) ^~ main.cpp:97:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<C.size();i++) ~^~~~~~~~~