Attribute VB_Name = "Examples"
'==========================================
' VBA For Loop in Excel - Companion Workbook
' Article: https://excelmaster.ai/blog/vba/vba-for-loop
' Tested on Excel 365 v2509, Excel 2021, Excel 2019
' Free to copy, modify, share. (c) ExcelMaster
'==========================================
Option Explicit

' ===== Example 1: Fill 10 cells with sequential numbers =====
Sub Example01_Basic()
    Dim i As Long
    For i = 1 To 10
        Sheets("01_Basic").Cells(i, 1).Value = i * 10
    Next i
End Sub

' ===== Example 2: Use Step to fill every other row =====
Sub Example02_Step()
    Dim i As Long
    For i = 1 To 20 Step 2
        Sheets("02_Step").Cells(i, 1).Value = "Row " & i
    Next i
End Sub

' ===== Example 3: Reverse loop - safely delete rows =====
' Why backward? Forward deletion shifts indices and causes you to skip rows.
Sub Example03_Reverse()
    Dim i As Long
    Dim ws As Worksheet
    Set ws = Sheets("03_Reverse")
    For i = 10 To 1 Step -1
        If ws.Cells(i, 2).Value = "DELETE" Then
            ws.Rows(i).Delete
        End If
    Next i
End Sub

' ===== Example 4: Exit For - stop on first match =====
Sub Example04_ExitFor()
    Dim i As Long
    For i = 1 To 1000
        If Sheets("04_ExitFor").Cells(i, 1).Value = "STOP" Then
            MsgBox "Found STOP at row " & i
            Exit For
        End If
    Next i
End Sub

' ===== Example 5: Nested loop - fill a 6x4 grid =====
Sub Example05_Nested()
    Dim r As Long, c As Long
    For r = 1 To 6
        For c = 1 To 4
            Sheets("05_Nested").Cells(r, c).Value = r * c
        Next c
    Next r
End Sub

' ===== Example 6: For Each over a Range =====
Sub Example06_ForEachRange()
    Dim cell As Range
    Dim total As Double
    For Each cell In Sheets("06_ForEachRange").Range("B2:B11")
        total = total + cell.Value
    Next cell
    Sheets("06_ForEachRange").Range("D2").Value = total
End Sub

' ===== Example 7: For Each over an Array =====
Sub Example07_ForEachArray()
    Dim names As Variant
    names = Array("Alice", "Bob", "Carol", "Dan")
    Dim n As Variant
    Dim i As Long
    i = 1
    For Each n In names
        Sheets("07_Array").Cells(i, 1).Value = n
        i = i + 1
    Next n
End Sub

' ===== Example 8: Real-world - copy rows where Amount > 200000 =====
Sub Example08_RealWorld()
    Dim ws As Worksheet
    Set ws = Sheets("08_RealWorld")
    Dim lastRow As Long
    lastRow = ws.Cells(ws.Rows.Count, 1).End(xlUp).Row
    ws.Range("F2:I100").ClearContents
    Dim outRow As Long
    outRow = 2
    Dim i As Long
    For i = 2 To lastRow
        If ws.Cells(i, 4).Value > 200000 Then
            ws.Cells(outRow, 6).Value = ws.Cells(i, 1).Value
            ws.Cells(outRow, 7).Value = ws.Cells(i, 2).Value
            ws.Cells(outRow, 8).Value = ws.Cells(i, 3).Value
            ws.Cells(outRow, 9).Value = ws.Cells(i, 4).Value
            outRow = outRow + 1
        End If
    Next i
End Sub

' ===== Bonus: Run all non-destructive examples =====
Sub RunAllExamples()
    Example01_Basic
    Example02_Step
    Example05_Nested
    Example06_ForEachRange
    Example07_ForEachArray
    Example08_RealWorld
    MsgBox "Done. Try Example03 (run Reset03_Reverse first if needed) and Example04 individually."
End Sub

' ===== Helper: Reset 03_Reverse sample data so Example03 can be re-run =====
' Example03 deletes rows in '03_Reverse'. After running it once, the DELETE flags
' are gone. Run this Reset before re-running Example03_Reverse to restore the
' original 10-row input (Items 1..10 with rows 3/6/9 marked DELETE).
Sub Reset03_Reverse()
    Dim ws As Worksheet
    Set ws = Sheets("03_Reverse")
    ws.Range("A1:B100").Clear
    Dim i As Long
    For i = 1 To 10
        ws.Cells(i, 1).Value = "Item " & i
        If i = 3 Or i = 6 Or i = 9 Then
            ws.Cells(i, 2).Value = "DELETE"
        Else
            ws.Cells(i, 2).Value = "KEEP"
        End If
    Next i
End Sub