Compilare: main.cpp: In function 'int euler(int)': main.cpp:32:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<x[csp].e.size();++i) ~^~~~~~~~~~~~~~~~ main.cpp:45:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ main.cpp: In function 'int main()': main.cpp:55:44: warning: narrowing conversion of 'x.std::vector<_Tp, _Alloc>::operator[]<el, std::allocator<el> >(((std::vector<el>::size_type)b)).el::e.std::vector<_Tp, _Alloc>::size<adat, std::allocator<adat> >()' from 'std::vector<adat>::size_type {aka long unsigned int}' to 'int' inside { } [-Wnarrowing] x[a].e.push_back({b,x[b].e.size(),0}); ~~~~~~~~~~~^~ main.cpp:56:46: warning: narrowing conversion of '(x.std::vector<_Tp, _Alloc>::operator[]<el, std::allocator<el> >(((std::vector<el>::size_type)a)).el::e.std::vector<_Tp, _Alloc>::size<adat, std::allocator<adat> >() - 1ul)' from 'std::vector<adat>::size_type {aka long unsigned int}' to 'int' inside { } [-Wnarrowing] x[b].e.push_back({a,x[a].e.size()-1,0}); ~~~~~~~~~~~~~^~ main.cpp:60:46: warning: narrowing conversion of '(x.std::vector<_Tp, _Alloc>::operator[]<el, std::allocator<el> >(((std::vector<el>::size_type)b)).el::e.std::vector<_Tp, _Alloc>::size<adat, std::allocator<adat> >() + 1ul)' from 'std::vector<adat>::size_type {aka long unsigned int}' to 'int' inside { } [-Wnarrowing] x[a].e.push_back({b,x[b].e.size()+1,0}); ~~~~~~~~~~~~~^~ main.cpp:61:46: warning: narrowing conversion of '(x.std::vector<_Tp, _Alloc>::operator[]<el, std::allocator<el> >(((std::vector<el>::size_type)a)).el::e.std::vector<_Tp, _Alloc>::size<adat, std::allocator<adat> >() - 1ul)' from 'std::vector<adat>::size_type {aka long unsigned int}' to 'int' inside { } [-Wnarrowing] x[b].e.push_back({a,x[a].e.size()-1,0}); ~~~~~~~~~~~~~^~ main.cpp:86:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<meg.size()-1;++i) ~^~~~~~~~~~~~~