Taking address of temporary [-fpermissive] - c++

Question

I know this question is already answered. But I just want to confirm what I understand.
Here is my snippet code. It comes from this.
#include <iostream>
using namespace std;
class Base
{
void a() { cout << "a "; }
void c() { cout << "c "; }
void e() { cout << "e "; }
// 2. Steps requiring peculiar implementations are "placeholders" in base class
virtual void ph1() = 0;
virtual void ph2() = 0;
public:
// 1. Standardize the skeleton of an algorithm in a base class "template method"
virtual ~Base() = default;
void execute()
{
a();
ph1();
c();
ph2();
e();
}
};
class One: public Base
{
// 3. Derived classes implement placeholder methods
/*virtual*/ void ph1() { cout << "b "; }
/*virtual*/ void ph2() { cout << "d "; }
};
class Two: public Base
{
/*virtual*/ void ph1() { cout << "2 "; }
/*virtual*/ void ph2() { cout << "4 "; }
};
int main()
{
Base *array[] =
{
&One(), &Two()
};
for (int i = 0; i < 2; i++)
{
array[i]->execute();
cout << '\n';
}
}
When I compiled, it gives the error as the title:
error: taking address of temporary [-fpermissive]
&One(), &Two()
error: taking address of temporary [-fpermissive]
&One(), &Two()
So, I try to find in the internet. And as they said:
&A() is creating a temporary object which gets destructed on exit of the full expression automagically...
When I changed error line
&One(), &Two()
to
new One(), new Two()
Then, it works.
But, how I make the origin code works like the author wrote? Should I use delete like
delete array[i];

Answer 1

With modern C++ features (11 and above) you can handle such polymorphic arrays with std::vector<std::unique_ptr<Base>>. vector allows automatic destruction and extension, and unique_ptr will destroy the object on its own destruction:
std::vector<std::unique_ptr<Base>> array;
array.emplace_back(new One());
array.emplace_back(new Two());
for(auto &p : array)
p->execute();
// no explicit cleanup is required here
You can choose other smart pointer classes as vector's elements, or even use std::array as fixed size container, but general idea is same for all approaches:
Try not to handle memory management manually, use STL primitives for
such low-level actions.