Getting all the combinations in an array

Lets extend it, so maybe we can see the pattern:

string[] arr = new string[] { "A", "B", "C", "D", "E" };

//arr[0] + arr[1] = AB
//arr[0] + arr[2] = AC
//arr[0] + arr[3] = AD
//arr[0] + arr[4] = AE

//arr[1] + arr[2] = BC
//arr[1] + arr[3] = BD
//arr[1] + arr[4] = BE

//arr[2] + arr[3] = CD
//arr[2] + arr[4] = CE

//arr[3] + arr[4] = DE

I see two loops here.

• The first (outer) loop goes from 0 to 4 (arr.Length – 1)
• The second (inner) loop goes from the outer loops counter + 1 to 4 (arr.Length)

Now it should be easy to translate that to code!