How to rearrange pairwise distinguishable numbers in C++?

Question

C++ / C#

There is such a task: "An array of dimension <= 100 pairwise distinguishable numbers is given. Print all permutations of these numbers." This is done in the windows console.
I can not understand what "pairwise distinguishable numbers" means. Explain, please.

Answer 1

take any two numbers from the array - and they are not equal. array example: 1 5 8 9. unlike array: 1 5 8 1 9.

Answer 2

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