Array
In this chapter you will learn:
What is an Array
An array is a collection of variables of the same type that are referred to by a common name. The length of an array is fixed. Array type is declared by putting square brackets after the data type. To declare a one-dimensional array, you will use this general form:
type[ ] array-name = new type[size];
System.Array is a base class for all arrays in C#.
Array elements can be of any type, including an array type.
System.Array implements IEnumerable and IEnumerable<T>,
you can use foreach iteration on all arrays in C#.
Arrays are zero indexed: an array with n elements is indexed from 0 to n-1.
using System;/*from j a v a2 s . co m*/
class MainClass
{
static void Main()
{
int[] arr = new int[] { 15, 20, 5, 25, 10 };
Console.WriteLine("GetType() = {0}", arr.GetType());
}
}
The code above generates the following result.
The default value of numeric array elements are set to zero, and reference elements are set to null. An array can be Single-Dimensional, Multidimensional or Jagged.
A jagged array is an array of arrays, and therefore its elements are reference types and are initialized to null.
The following code declare an array type for int.
int[] intArray;
The size of an array is declared when allocating memory for its elements.
We use the new operator to allocate memory for array.
int[] intArray = new int[100];
To reference an element from an array, we put the index inside the square bracket.
intArray[2]
The index of an array starts at 0, so the code
above is referencing the third element in intArray.
The following code sets the elements in an array with index and then output them:
using System;// ja v a 2 s. c om
class Program
{
static void Main(string[] args)
{
int[] intArray = new int[10];
intArray[0] = 3;
intArray[1] = 4;
intArray[2] = 5;
Console.WriteLine(intArray[0]);
Console.WriteLine(intArray[1]);
Console.WriteLine(intArray[2]);
}
}
The output:
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What you will learn in the next chapter: