Loop all pairs

Let's say I have this array:

{a, b, c, d, e}

How can I look through all the possible pairs?

a, b
a, c
a, d
a, e
b, c
b, d
b, e
c, d
c, e
d, e

Fictional language syntax please.

>>19
If it was a permutation then ("A","B") and ("B","A") would be different.