C# 4 and .NET 4

130 ❘ ChaPTer 6 ArrAys And tuples
array initialization
After declaring an array, memory must be allocated to hold all the elements of the array. An array is a
reference type, so memory on the heap must be allocated. You do this by initializing the variable of the
array using the new operator with the type and the number of elements inside the array. Here you specify the
size of the array:
myArray = new int[4];
Value and reference types are covered in Chapter 3, “ Objects and Types .”
With this declaration and initialization, the variable myArray references four integer values that are
allocated on the managed heap (see Figure 6 - 1).
Stack
myArray
Managed Heap
int
int
int
int
figure 6-1
The array cannot be resized after the size was specifi ed without copying all elements. If
you don ’ t know the number of elements that should be in the array in advance, you can
use a collection (see Chapter 10).
Instead of using a separate line to declare and initialize an array, you can use a single line:
int[] myArray = new int[4];
You can also assign values to every array element using an array initializer. Array initializers can be
used only while declaring an array variable, not after the array is declared:
int[] myArray = new int[] {4, 7, 11, 2};
If you initialize the array using curly brackets, the size of the array can also be left out, because the
compiler can count the number of elements itself:
int[] myArray = new int[] {4, 7, 11, 2};
There ’ s even a shorter form using the C# compiler. Using curly brackets you can write the
array declaration and initialization. The code generated from the compiler is the same as in the
previous example:
int[] myArray = {4, 7, 11, 2};
accessing array elements
After an array is declared and initialized, you can access the array elements using an indexer. Arrays
only support indexers that have integer parameters.
www.it-ebooks.info