[Year 12 SofDev] Code Optimisation

[Vella, James]

I'm guessing it's partly to do with the fact that your code has 2x FOR loops compared to his 1.

His code has only one condition to check, while your code, while providing the same functionality, has two conditions to check.

http://www.programming4scientists.com/2008/10/03/how-to-optimise-code/ - I'll admit I did cheat a bit to back my thoughts up...look at the Code re-ordering section explains the condition checking part nicely...I think.


Mr James Vella
MacKillop College

-----Original Message-----

Today's Topics:

   1. Code optimization (ATKINSON-BUCK, Damien)


Hi folks,
            I've just started going through loops and leading into multi-dimensional arrays. Last night the boys did the first 2 exercises of Marks old "Arrays and Loops Exercises". In the increasing stars program, he managed to do it in 2 less lines of code and so I was curious as to which was physically faster. I put a timer class into the code to test it, and his was dramatically faster. 0.415 sec versus 0.084 sec Anyone out there able to explain why?
Cheers
Damien

    Sub Main()

        'My version
        Dim firstTick As TickTimer = New TickTimer()
        For counter As Integer = 1 To 100
            For InnerCounter = 1 To counter
                Console.Write("*")
            Next
            Console.WriteLine()
        Next

        'Adems version
        Dim secondTick As TickTimer = New TickTimer()
        Dim star As String = "*"
        For counter2 As Integer = 1 To 100
            Console.WriteLine(star)
            star += "*"
        Next

        'display timing
        Console.WriteLine(firstTick.DeltaSeconds("Mine"))
        Console.WriteLine(secondTick.DeltaSeconds("Adems"))
        'wait til key pressed
        Console.ReadKey()
    End Sub


    Public Class TickTimer
        Public currentTicks As Long
        Public lastTicks As Long = System.DateTime.Now.Ticks
        Public retVal As String
        ''' <summary>
        ''' Calculates the seconds it took since the class was instantiated until this method
        ''' is first invoked and for subsequent calls since the previous time the method was called
        ''' </summary>
        ''' <param name="message">Message (e.g. "The last query took ")</param>
        ''' <returns>The passed string followed by the seconds: "          The last query took,     0.3456"</returns>
        ''' <remarks>To see how long it takes a method to execute instantiate this class at its
        ''' very begining and call this method just before it returns; Log the result with     Debug.Writeln or something similar</remarks>
        Public Function DeltaSeconds(ByVal message As String) As String
            currentTicks = System.DateTime.Now.Ticks
            retVal = String.Format("{0}, {1}", message.PadLeft(100), ((currentTicks - lastTicks) / TimeSpan.TicksPerSecond).ToString().PadRight(15))
            lastTicks = currentTicks
            Return retVal
        End Function
    End Class



Damien Atkinson-Buck
Head of Learning Area: Technology/Arts
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