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C# Tutorial · Control Flow · Lesson 10 of 22

C# Arrays

Single and multi-dimensional arrays, indexes, ranges and Array methods.

Arrays

Arrays have a fixed length. Indexes start at 0; ^1 means "last", and ranges like [1..3] slice:

Example 1
int[] nums = { 42, 7, 19, 3 };
string[] names = new string[3];   // filled with null
names[0] = "Ada";
Console.WriteLine($"{nums.Length} {nums[0]} {nums[^1]}");
Console.WriteLine(string.Join(",", nums[1..3]));
Array.Sort(nums);
Console.WriteLine(string.Join(",", nums));
Console.WriteLine(Array.IndexOf(nums, 19) + " " + nums.Contains(7));

int[,] grid = { { 1, 2, 3 }, { 4, 5, 6 } };
Console.WriteLine($"{grid[1, 2]} rows={grid.GetLength(0)} cols={grid.GetLength(1)}");

Output

4 42 3
7,19
3,7,19,42
2 True
6 rows=2 cols=3

Run this on your computer — see “Get Started” for setup.

Need a list that grows? Use List<T>.

Test yourself

What does arr[^1] return?

  1. The first element
  2. The last element
  3. An error
  4. The length
Show answer

Answer: The last element

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