F#

This solution is very flexible -- it allows you to pick people in batches, so you won't have to run it again for a little while. Supply the number as the first argument to the program:

[<EntryPoint>] let main argv = let getRandom (min, max) = (new System.Random()).Next (min, max) let pickBuyers people times = List.init times (fun _ -> List.nth people (getRandom (0, List.length people))) printfn "%A" (pickBuyers ["John"; "Jeff"; "Emma"; "Steve"; "Julie"] <| System.Int32.Parse argv.[0]) 0 

Exploits a common mistake when learning random numbers, so you probably caught this if you know the basics of System.Random. Instantiating Random() uses the time as a seed, and calling it in quick succession will cause it to seed exactly the same over and over until the time changes.

F#

This solution is very flexible -- it allows you to pick people in batches, so you won't have to run it again for a little while. Supply the number as the first argument to the program:

[<EntryPoint>] let main argv = let getRandom (min, max) = (new System.Random()).Next (min, max) let pickBuyers people times = List.init times (fun _ -> List.nth people (getRandom (0, List.length people))) printfn "%A" (pickBuyers ["John"; "Jeff"; "Emma"; "Steve"; "Julie"] <| System.Int32.Parse argv.[0]) 0 

Exploits a common mistake when learning random numbers, so you probably caught this if you know the basics of System.Random. Instantiating Random() uses the time as a seed, and calling it in quick succession will cause it to seed exactly the same over and over until the time changes.

However (as pointed out by @kernigh), the more elements you generate at once, the more likely it is to roll over to the next millisecond before it's finished. This will cause the next RNGs to get seeded with a different number, thus changing the resulting number. This will happen every millisecond(?).

F#

This solution is very flexible -- it allows you to pick people in batches, so you won't have to run it again for a little while. Supply the number as the first argument to the program:

[<EntryPoint>] let main argv = let getRandom (min, max) = (new System.Random()).Next (min, max) let pickBuyers people times = List.init times (fun _ -> List.nth people (getRandom (0, List.length people))) printfn "%A" (pickBuyers ["John"; "Jeff"; "Emma"; "Steve"; "Julie"] <| System.Int32.Parse argv.[0]) 0 

A common mistake when learning random numbers, instantiating Random() uses the time as a seed, and calling it in quick succession will cause it to seed exactly the same over and over until the time changes.

F#

This solution is very flexible -- it allows you to pick people in batches, so you won't have to run it again for a little while. Supply the number as the first argument to the program:

[<EntryPoint>] let main argv = let getRandom (min, max) = (new System.Random()).Next (min, max) let pickBuyers people times = List.init times (fun _ -> List.nth people (getRandom (0, List.length people))) printfn "%A" (pickBuyers ["John"; "Jeff"; "Emma"; "Steve"; "Julie"] <| System.Int32.Parse argv.[0]) 0 

Exploits a common mistake when learning random numbers, so you probably caught this if you know the basics of System.Random. Instantiating Random() uses the time as a seed, and calling it in quick succession will cause it to seed exactly the same over and over until the time changes.