livedoor ナレッジ

変数の宣言はあっていますか？またこのコーディングについて解説がいただけたらうれしいです。

Dim lastRow As Long
Dim t_day As Variant
Dim serch As Variant
Dim result As Variant
Dim d_count As Long
Dim r_count As Long

   
   lastRow = Range("G" & Rows.Count).End(xlUp).Row
   For Each t_day In Range("G12:G" & lastRow)
       If t_day <> "" Then
       If IsDate(t_day) Then
           serch = Application.Text(t_day, Range("D12").NumberFormat)
           Set result = Columns("D:D").Find( _
                       What:=serch, _
                       LookIn:=xlValues, _
                       LookAt:=xlWhole, _
                       SearchOrder:=xlByRows, _
                       SearchDirection:=xlNext, _
                       MatchCase:=False, MatchByte:=False)
           
           If Not result Is Nothing Then
               d_count = 0
               r_count = 0
               Do
                   If Range("F" & result.Row - r_count) <> "★" Then _
                           d_count = d_count + 1
                   If d_count = 4 Then Exit Do
                   r_count = r_count + 1
               Loop
               Range("H" & t_day.Row) = Range("D" & result.Row - r_count)
           End If
           
       End If
       End If
   Next
   Set result = Nothing

End Sub