Other April fools quite difficult and a bit unfair quiz

Erel · Apr 1, 2021

code:

B4X:

Sub Process_Globals
    Private fx As JFX
    Private MainForm As Form
    Private xui As XUI 
    Private Button1 As B4XView
    Private TextField1 As B4XView
    Private TextField2 As B4XView
    Private lblResult As B4XView
End Sub

Sub AppStart (Form1 As Form, Args() As String)
    MainForm = Form1
    MainForm.RootPane.LoadLayout("Layout1")
    MainForm.Show
    Dim r As Reflector
#region Secret
 '3 lines here...................................
#end region

End Sub


Sub Button1_Click
    Dim FirstNumber As Int = TextField1.Text
    Dim SecondNumber As Int = TextField2.Text
    lblResult.Text = SumInts (Array(FirstNumber, SecondNumber))
End Sub

Sub SumInts (Ints As List) As Int
    Dim sum As Int = 0
    For Each i As Int In Ints
        sum = sum + i
    Next
    Return sum
End Sub

alwaysbusy · Apr 1, 2021

Well this is just great! There goes my productive afternoon...

Erel · Apr 1, 2021

B4X:

Sub Button1_Click
    Log(SumInts(Array(1, 14)))    
End Sub

Star-Dust · Apr 1, 2021

B4X:

    #region Secret
    Do While True
        If IsNumber(lblResult.Text) Then
            If 10<lblResult.Text Then
                Dim Val1 As Int = Min(TextField1.Text,TextField2.Text)
                Dim Val2 As Int = Max(TextField1.Text,TextField2.Text)
            
                Val2=(Val2 Mod 10)-Floor(Val2/10)
                lblResult.Text=(Val1+Val2)
            End If
        End If
        Sleep(0)
    Loop
    #end region

LucaMs · Apr 1, 2021

I don't understand where the quiz is; that's the normal outcome of Erel's programming, isn't it?
?

Mine often

Alexander Stolte · Apr 1, 2021

LucaMs said:
I don't understand where the quiz is; that's the normal outcome of Erel's programming, isn't it?
?

I agree with you, sometimes I see values in the log where I doubt all my experience ?

Sandman · Apr 1, 2021

I have no idea how to do it with code, but it seems to me...

...that some reflector magic is modifying the second element in the input array to SumInts so that it's mod 11.

agraham · Apr 1, 2021

Hmm! It seems to be doing something naughty with reflection but I don't think its related to intercepting the click event as the second example logs the output of SumInts directly in the click event so it seems to be modifying either the parameter list values or the return value of Sub SumInts somehow. Moreover it's doing it permanently with only three lines of code run once only.

I don't think it's Mod 11 as the second example has no numeric values in the TextFields.

I wrote the jReflection library but have no idea what's going on here I shall ponder further after a fortifying lunch.

Star-Dust · Apr 1, 2021

agraham said:
I don't think it's Mod 11 as the second example has no numeric values in the TextFields.

check the content of the result label

agraham · Apr 1, 2021

Star-Dust said:
check the content of the result label

Why? It's not set in Erel's second example so it can't have anything to do with it.

LucaMs · Apr 1, 2021

I only know that Erel, instead of giving us a present for Easter ?, gave us something to rack our brains.
For now I have too much headache to think about it, I prefer to wait for your solution.
(It could be anything, even intercept and replace the function)

Erel · Apr 1, 2021

LucaMs said:
For now I have too much headache to think about it, I prefer to wait for your solution.

That's the correct approach. As I wrote, it is an unfair quiz. It is unfair because it manipulates something in the underlying Java type system.

Nice solution @Star-Dust but this is not what I did. As you can see in the second example, it is not related to the UI.

Two hints:
1. The first hidden line is:

B4X:

Dim cache() As Object = r.GetStaticField("java.lang.Integer$IntegerCache", "cache")

2. More outputs:

B4X:

Log(SumInts(Array(1, 14)))    '4
Log(SumInts(Array(10, 2)))    '12
Log(SumInts(Array(8, 3)))    '11
Log(SumInts(Array(14, 2)))    '5

Sandman · Apr 1, 2021

In that case I'd like to adjust my guess to...

...all integers are mod 11. (Made via IntegerCache, which I have no clue to what it is. Probably some sort of cache for integers. )

Star-Dust · Apr 1, 2021

Sandman said:
In that case I'd like to adjust my guess to...

...all integers are mod 11. (Made via IntegerCache, which I have no clue to what it is. Probably some sort of cache for integers. )

Java Integer Cache - GeeksforGeeks

A Computer Science portal for geeks. It contains well written, well thought and well explained computer science and programming articles, quizzes and practice/competitive programming/company interview Questions.

www.google.com

agraham · Apr 1, 2021

Sandman said:
.all integers are mod 11.

Could be so
This seems to give the 'expected' results when logged as in the second example but messes up the numeric characters in the UI so it is not the whole answer. It's too many lines as well

B4X:

    #region Secret
    Dim r As Reflector 
    Dim cache() As Object = r.GetStaticField("java.lang.Integer$IntegerCache", "cache")
    For i = 0 To cache.Length -1
        Dim j As Int = cache(i) Mod 11
        cache(i) = j
    Next 
    #end region

LucaMs · Apr 1, 2021

agraham said:
Could be so
This seems to give the 'expected' results when logged as in the second example but messes up the numeric characters in the UI so it is not the whole answer. It's too many lines as well

B4X:

#region Secret Dim r As Reflector Dim cache() As Object = r.GetStaticField("java.lang.Integer$IntegerCache", "cache") For i = 0 To cache.Length -1 Dim j As Int = cache(i) Mod 11 cache(i) = j Next #end region

agraham · Apr 1, 2021

Changing just a subset of integer values outside of the character values range seems to fix the UI problem. Still too many lines of code though!

B4X:

    #region Secret
    Dim r As Reflector  
    Dim cache() As Object = r.GetStaticField("java.lang.Integer$IntegerCache", "cache")
    For i = 107 To 148 'cache.Length -1
        Dim j As Int = cache(i) Mod 11
        cache(i) = j
    Next  
    #end region

Erel · Apr 1, 2021

Almost. Tip: only 14 is affected. Not Mod 11.

Two lines are enough.

agraham · Apr 1, 2021

Erel said:
only 14 is affected

14 what? The integer value 14 or 14 values in total?

Erel · Apr 1, 2021

agraham said:
The integer value 14

Yes

Other April fools quite difficult and a bit unfair quiz

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