What is the best way to instantiate a class?

Question

C++ / C#

What is the best way to instantiate a class?
1 way:

class A {}

class B
{
   A instance;
   public void SomeMethod()
      {
         instance = new A();
      }
}

2 way:

class A {}

class B
{
   public void SomeMethod()
      {
         A instance = new A();
      }
}

Answer 1

The first way creates a class field, the second way creates a local variable. If other methods need a previously created instance, or when this method is called again, the same instance is needed, then make a field. If you need a new instance every time you call a method, make it a local variable. Remember that after the method ends, all local variable data is deleted (unless you return an instance via method return).