C# 0 The Complete Reference

x

, which is 10. In the program, 

p

 is declared as a pointer to an 

int

and

q

 as a pointer to an 

int

 pointer.

One last point: Do not confuse multiple indirection with high-level data structures, such 

as linked lists. These are two fundamentally different concepts.

Arrays of Pointers

Pointers can be arrayed like any other data type. The declaration for an 

int

 pointer array of 

size 3 is

int * [] ptrs = new int * [3];

To assign the address of an 

int

 variable called 

var

 to the third element of the pointer array, 

write

ptrs[2] = &var;

To find the value of 

var

, write

*ptrs[2]

sizeof

When working in an unsafe context, you might occasionally find it useful to know the size, 

in bytes, of one of C#’s value types. To obtain this information, use the 

sizeof

 operator. It 

has this general form:

sizeof(

type

)

Here, type is the 

type

 whose size is being obtained. In general, 

sizeof

 is intended primarily for

special-case situations, especially when working with a blend of managed and unmanaged 

code.

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stackalloc

You can allocate memory from the stack by using 

stackalloc

. It can be used only when 

initializing local variables and has this general form:

type *p

 = stackalloc 

type

[

size

]

Here, 

p

 is a pointer that receives the address of the memory that is large enough to hold 

size

number of objects of 

type.

 Also, 

type

 must be a nonreference type. If there is not room on the 

stack to allocate the memory, a