CSng（）或x 1F？

Question

假設選項Strict On; a和b - 整數

Dim mySingle as Single = a/b ' implicit conversion error 

解A）

Dim mySingle as Single = CSng(a/b) ' CSng 

溶液B）

Dim mySingle as Single = a * 1F/b ' x 1F 

什麼溶液優選是？
如果性能很重要，需要採取什麼解決方案？

Answer 1

出於可讀性和揭示意圖，我會去答：

Dim mySingle as Single = CSng(a/b) ' CSng 

使用A，你都清楚地說，我知道計算返回不同的類型，這就是我想要的。對於性能 - 我運行了一個快速的微基準測試，每次測試100萬次迭代，差異在毫秒級到亞毫秒級之間，與CSing有很小的優勢。不要擔心這種轉換的性能（當然，您需要自行測試）。

基準代碼：

Sub Main() 
    Dim mySingle As Single 
    Dim a As Integer = 10 
    Dim b As Integer = 5 

    Dim iterations As Integer = 1000000 

    Dim sw As New Stopwatch() 

    sw.Start() 
    For i As Integer = 1 To iterations 
     mySingle = CSng(a/b) ' CSng ' 
    Next 
    sw.Stop() 

    Console.WriteLine(String.Format("CSng(a/b) - {0}", sw.Elapsed)) 


    sw.Reset() 
    sw.Start() 
    For i As Integer = 1 To iterations 
     mySingle = a * 1.0F/b ' x 1F ' 
    Next 
    sw.Stop() 

    Console.WriteLine(String.Format(" a * 1.0F/b - {0}", sw.Elapsed)) 

End Sub