template <class T2>
void sum(T2 op1)
{
cout << "###";
}
int main() {
sum<double>(1); //1
void(*pt)(int) = sum; //2
void(*pt1)(int) = sum<int>; //3
void(*pt2)<int>(int) = & sum; //4
void(*pt3)(int) = & sum; //5
return 0;
}