NP119 value types & reference types

Thank you for your explanation.

Suppose you have this class:

public class MyClass
{
   public int MyInt;
   public double MyDouble;
   public string MyString;

   public MyClass(int myInt, double myDouble, string myString)
   {
       MyInt = myInt;
       MyDouble = myDouble;
       MyString = myString;
   }
}

Now, MyClass is of course a reference type and so when you execute this line:

MyClass mc = new MyClass(3, 4.5, "hello");

an instance of MyClass is created on the heap.

This instance requires 24 bytes of storage, broken down as follows:

   8 bytes overhead  (assuming a 32 bit system)
   4 bytes for MyInt
   8 bytes for MyDouble
   4 bytes for a pointer to where MyString is stored elsewhere on the heap.

So, it will be seen that the value types, MyInt and MyDouble, are allocated on the heap because they are fields of a reference type.

Similarly, if you have this:

int[] ia = new int[]{1,2,3};

the array is a reference type and so is allocated on the heap. It contains three integers stored one after the other and requiring 4 bytes of storage each, plus the overhead required for the array itself (8 bytes plus 4 bytes for the length).

Finally, if you have this within a method:

int a = 3;
object o = a;

then the integer is 'boxed' on the heap . The wrapper needs 8 bytes of overhead plus 4 further bytes to hold the copy of the integer.

Notice that value types don't require any overhead themselves.

I mean in which specific circumstances Value types are allocated on the heap. It is much appreciated if you can demonstrate with example.    

Otherwise means 'in other circumstances'.

So, in the context of my earlier post, it means in circumstances other than those described in 2(i) and 2(ii).

Thank you for your explanation.