19. oktober 2014 - 11:51
Der er
2 kommentarer
Nummer generator
Hej jeg har brug for gentagne gange at trække et tilfældigt nummer uden at det trukne nummer gentages. Generatoren skal bruges til en Quiz. Jeg har uden held forsøgt at få denne rutine til at virke, men af og til kommer det samme nummer igen. Nogen der kan gennemskue hvad der er galt?
Randomize()
Antal = Tabel1BindingSource.Count
Lantal.Text = Antal
Dim C As New Collection, I As Integer
For I = 1 To Antal
C.Add(CStr(I), CStr(I))
Next I
I = Int(Rnd() * C.Count + 1)
Tabel1BindingSource.Position = (C.Item(I))
C.Remove(I)
19. oktober 2014 - 15:59
#1
Grundliggende er der 2 teknikker.
1) du traekker et tilfaeldigt tal indtil dufaar et som ikke er truller foer
2) du prefiller en liste med alle muligheder, shuffler og tager de foerste fra dey
19. oktober 2014 - 16:20
#2
Til inspiration:
Imports System
Imports System.Collections.Generic
Imports System.Linq
Namespace E
Public Class Program
Private Shared rng As New Random()
Public Shared Function Bad(n As Integer, min As Integer, max As Integer) As List(Of Integer)
Dim res As New List(Of Integer)()
For i As Integer = 0 To n - 1
res.Add(rng.Next(min, max + 1))
Next
Return res
End Function
Public Shared Function Good1(n As Integer, min As Integer, max As Integer) As List(Of Integer)
Dim res As New List(Of Integer)()
For i As Integer = 0 To n - 1
Dim v As Integer
Do
v = rng.Next(min, max + 1)
Loop While res.Contains(v)
res.Add(v)
Next
Return res
End Function
Public Shared Function Good2(n As Integer, min As Integer, max As Integer) As List(Of Integer)
Dim res As New List(Of Integer)()
For i As Integer = min To max
res.Add(i)
Next
Return res.Select(Function(v) New Tuple(Of Integer, Integer)(v, rng.Next())).OrderBy(Function(r) r.Item2).Select(Function(r) r.Item1).Take(n).ToList()
End Function
Public Shared Sub Main(args As String())
Console.WriteLine("Wrong:")
For Each v As Integer In Bad(5, 1, 10)
Console.WriteLine(v)
Next
Console.WriteLine("Check for duplicate:")
For Each v As Integer In Good1(5, 1, 10)
Console.WriteLine(v)
Next
Console.WriteLine("Shuffle:")
For Each v As Integer In Good2(5, 1, 10)
Console.WriteLine(v)
Next
Console.ReadKey()
End Sub
End Class
End Namespace
