vba - loop through 3 columns - excel

Question

There are 4 columns on my excel.
For every element in column A, I would like to loop through every element column C. If the element in column C equal to column A, then it return the value of column D in column B.
For example, B4 should return "dog". B5 should return "egg". B6 should return "cat".
I ran my VBA code. All the value in column B returns "egg". Could someone have a look with my below VBA code please?
Sub testing_click()
Dim x As Variant
Dim arr1 As Variant
Dim i , r As Long
arr1 = Worksheets("testing").Range("A1:A" & Range("A" & Rows.Count).End(xlUp).Row).Value
For Each x In arr1
For r = 1 To 5
If x = Trim(Worksheets("testing").Cells(r, "c").Value) Then
For i = 1 To Worksheets("testing").Range("a1048576").End(xlUp).Row
Worksheets("testing").Cells(i, "b").Value = Worksheets("testing").Cells(r, "d").Value
Next i
End If
Next r
Next x
End Sub

Answer 1

Just had one too many loops in there. What it was actually doing was finding the first value correctly, and putting it in all 12 rows of column "B". Then finding the second value, and re-assigning all 12 rows of column "B".
Get rid of the innermost loop, add counter in it's place with the same name, and you're good to go. Now, instead of looking through all cells in column "A", it only looks through the populated ones, and will terminate the inner loop as soon as it has a match.
Also corrected a mistake in the declarations. Dim i, r As Long actually only casts r as long, and i as Variant. Dim i as Long, r as Long will capture them both as Long types.
Hope it helps!
Sub testing_click()
Dim x As Variant
Dim arr1 As Variant
Dim i as Long, r As Long
arr1 = Worksheets("testing").Range("A1:A" & Range("A" & Rows.Count).End(xlUp).Row).Value
'initialize row counter out here
i = 1
For Each x In arr1
For r = 1 To 5
If x = Trim(Worksheets("testing").Cells(r, "c").Value) Then
Worksheets("testing").Cells(i, "b").Value = Worksheets("testing").Cells(r, "d").Value
'Increment row counter and exit inner loop
i = i + 1
Exit For
End If
Next r
Next x
End Sub

Answer 2

arr1 must be Dim'ed as array ... e.g. Dim arr1() As Variant
I also recommend to substitute the End(xlUpDownLeftRightHomeEnd)'s by more VBA like loop constructs, e.g.
Sub ClassicalLoops()
Dim OuterLoop As Integer, InnerLoop As Integer
Dim DataRange As Range, LookupRange As Range
Set DataRange = [A1]
Set LookupRange = [C1]
OuterLoop = 1
Do While DataRange(OuterLoop, 1) <> ""
InnerLoop = 1
Do While LookupRange(InnerLoop, 1) <> ""
If DataRange(OuterLoop, 1) = LookupRange(InnerLoop, 1) Then
DataRange(OuterLoop, 2) = LookupRange(InnerLoop, 2)
Exit Do
Else
InnerLoop = InnerLoop + 1
End If
Loop
OuterLoop = OuterLoop + 1
Loop
End Sub