Declaring Arrays
To declare an array in C#, you can use the following syntax:
datatype[ ] arrayName;
where,
- datatype is used to specify the type of
elements to be stored in the array.
- specifies the rank of the array. The rank
specifies the size of the array.
- arrayName specifies the name of the
array.
For example
double[ ] balance;
Initializing an Array
Declaring an array does not initialize the array in the memory. When the array
variable is initialized, you can assign values to the array.
Array is a reference type, so you need to use the new keyword to create an
instance of the array.
For example
double[ ] balance = new double[10];
Assigning Values to an Array
You can assign values to individual array elements, by using the index number,
like:
double[ ] balance = new double[10];
balance[0] = 4500.0;
You can assign values to the array at the time of declaration, like:
double[ ] balance = { 2340.0, 4523.69, 3421.0};
You can also create and initialize an array, like:
int [ ] marks = new int[5] { 99, 98, 92, 97, 95};
In the preceding case, you may also omit the size of the array, like:
int [ ] marks = new int[ ] { 99, 98, 92, 97, 95};
You can also copy an array variable into another target array variable. In that
case, both the target and source would point to the same memory location:
int
[ ] marks = new int[ ]
{ 99, 98, 92, 97, 95};
int[ ]
score = marks;
When you create an array, C# compiler implicitly initializes each array element
to a default value depending on the array type. For example for an int array all
elements would be initialized to 0.
Accessing Array Elements
An element is accessed by indexing the array name. This is done by placing the
index of the element within square brackets after the name of the array. For
example:
double salary = balance[9];
Following is an example which will use all the above mentioned three concepts
viz. declaration, assignment and accessing arrays:
using
System;
namespace
ArrayApplication
{
class MyArray
{
static void
Main(string[] args)
{
int[] n = new
int[10];
/* n is an array of 10 integers */
int i, j;
/* initialize elements of array n */
for (i = 0; i < 10; i++)
{
n[i] = i +
100;
}
/* output each array element's value */
for (j = 0; j < 10; j++)
{
Console.WriteLine("Element[{0}]
= {1}", j, n[j]);
}
Console.ReadKey();
}
}
}
When the above code is compiled and executed, it produces following result:
Element[0] = 100
Element[1] = 101
Element[2] = 102
Element[3] = 103
Element[4] = 104
Element[5] = 105
Element[6] = 106
Element[7] = 107
Element[8] = 108
Element[9] = 109
Using the foreach Loop
In the previous example, we have used a for loop for accessing each array
element. You can also use a foreach statement to iterate through an array.
using
System;
namespace
ArrayApplication
{
class MyArray
{
static void
Main(string[] args)
{
int[] n = new
int[10];
/* n is an array of 10 integers */
/* initialize elements of array n */
for (int i = 0;
i < 10; i++)
{
n[i] = i +
100;
}
/* output each array element's value */
foreach (int j
in n)
{
int i = j - 100;
Console.WriteLine("Element[{0}]
= {1}", i, j);
i++;
}
Console.ReadKey();
}
}
}
When the above code is compiled and executed, it produces following result:
Element[0] = 100
Element[1] = 101
Element[2] = 102
Element[3] = 103
Element[4] = 104
Element[5] = 105
Element[6] = 106
Element[7] = 107
Element[8] = 108
Element[9] = 109
C# Arrays in Detail
Arrays are important to C# and should need lots of more detail. There are
following few important concepts related to array which should be clear to a C#
programmer:
|
Concept
|
Description |
| Multi-dimensional arrays |
C# supports multidimensional arrays.
The simplest form of the multidimensional array is the two-dimensional
array. |
| Jagged arrays |
C# supports multidimensional arrays,
which are arrays of arrays. |
| Passing arrays to functions |
You can pass to the function a
pointer to an array by specifying the array's name without an index. |
| Param arrays |
This is used for passing unknown
number of parameters to a function. |
| The Array Class |
Defined in System namespace, it is
the base class to all arrays, and provides various properties and
methods for working with arrays. |