How to set a cell value depeinding on a specefic cell value - excel

Question

I am trying to automate the excel sheet by checking the value of a specific cell, and setting multiple columns with a value.
For example if A1 cell is "2" then I would like all the cells from B2:D54 to be the value equal to 0. I have a code written but it looks like it is wrong.
Private Sub Worksheet_Change(ByVal Target As Range)
//this selects the cell C3 and checks if the value if is 0619
If Range("C3")="0619"
Dim example As Range
Set example =Range("E3:AE53")
example.Value = 0
End if
End Sub
Edit - Added Then, but still not working.
Private Sub Worksheet_Change(ByVal Target As Range)
//this selects the cell C3 and checks if the value if is 0619
If Range("C3")="0619" Then
Dim example As Range
Set example =Range("E3:AE53")
example.Value = 0
End if
End Sub

Answer 1

You are missing Then in the line with If
Comments in VBA are started with ', not // so this will not parse correctly.
If Range("C3")="0619" Bear in mind Excel will remove leading zeros from numbers. Only have leading zeros if you will be formatting the value as text.
Edit: If Range("C3").Value better than If Range("C3")
Private Sub Worksheet_Change(ByVal Target As Range)
'this selects the cell C3 and checks if the value if is 0619
If Range("C3").Value = "0619" Then
Dim example As Range
Set example = Range("E3:AE53")
example.Value = 0
End If
'
Range("A1").Select
End Sub

Answer 2

only perform the work if C3 is changed.
if C3 is a number formatted as 0000 (leading zero) then use If Range("C3").Text ="0619" Then
as mentioned in comments, disable events or your routine will try to run on top of itself when you change the values in the cells.
event driven sub procedures should have error control
Code:
Private Sub Worksheet_Change(ByVal Target As Range)
if not intersect(target, range("C3")) is nothing then
on error goto safe_exit
application.enableevents = false
select case range("C3").text
case "0619"
Range("E3:AE53") = 0
case else
'do nothing
end select
End if
safe_exit:
application.enableevents = true
End Sub
I've changed your criteria check to a Select Case statement to make it easier to accommodate additional conditions.