Array is a collection of variable of same data type. If you have declare 1000 long variable, then you can declare an long type array of 1000 size. The value of array can be access using index position of array. The first index position of array is zero.
In C#, two types of array: Single Dimensional Array and Multi Dimensional Array. You can use both type of array easily and can access its element using loop constructs or index position.