setting alternate columns number format - google-apps-script

Question

I have a sheet where we have a product name in column A, row 3. In cells B1 and C1 we have the date and then in B2 stock and C2 price
26/3/21 26/3/21
Thingymabob 3 5
I want to step along the columns C, E, G etc. until the last column formatting them to $#.##
I can't find a way to format column (index) so I've found an old bit of code on here that converts the index to a letter then I've tried to use that letter to say
"var column = sheet.getRange("C2:C")"
"column.setNumberFormat("[$€]#,##0.00");"
No joy though. Here's the function, please help!
function formatPriceColumns() {
var spreadsheet = SpreadsheetApp.getActiveSpreadsheet();
var sheet = spreadsheet.getSheetByName("PriceHistory");
var temp = ""
var letter = "";
var lastCol = sheet.getLastColumn();
var lastRow = sheet.getLastRow();
for(i = 3; i <= lastCol; i = i + 2) {
temp = (i - 1) % 26;
letter = String.fromCharCode(temp + 65) + letter;
i = (i - temp - 1) / 26;
var needString = "\"" + letter + "3" + ":" + letter + lastRow + "\""
var column = sheet.getRange(needString)
column.setNumberFormat("[$€]#,##0.00");
}
}

Answer 1

Well there were a number of issues!
Using i twice was the least among them. Also the scope fo the variables and most importantly, not passing a string.
The corrected code looks like this:
function formatColumns() {
var spreadsheet = SpreadsheetApp.getActiveSpreadsheet();
var sheet = spreadsheet.getSheetByName("PriceHistory");
var lastCol = sheet.getLastColumn();
var lastRow = sheet.getLastRow();
for(i = 5; i <= lastCol; i = i + 2) {
var temp = ""
var letter = ""
var column = 0
column = i
temp = (column - 1) % 26;
letter = String.fromCharCode(temp + 65) + letter;
var column = sheet.getRange(letter + "3:" + letter + lastRow)
column.setNumberFormat("[$€]#,##0.00");
}
}