Batch File input validation - Make sure user entered an integer

Question

I\'m experimenting with a Windows batch file to perform a simple operation which requires the user to enter a non-negative integer. I\'m using simple batch-file techniques t

Answer 1

If you want some sort of a loop and default set up for that particular question, then here's my method for doing this.

Notes on the code within.

@echo off
setlocal EnableDelayedExpansion
set "ans1_Def=2"

:Q1
set /p "ans1=Opt 1 of 1 [Value 1-5 / Default !ans1_Def!]: "

:: If not defined section. This will use the default once the ENTER key has been
:: pressed and then go to :Q2.
if not defined ans1 (
  echo/ & echo ENTER hit and the default used. Default is still: !ans1_Def! & echo/
  set "ans1=!ans1_Def!" && goto :Q2 )

:: This section will check the validity of the answer. The "^[1-5]$" will work
:: for only numbers between one and five in this example but this can be changed
:: to pretty much suit the majority of cases. This section will also undefine
:: the ans1 variable again so that hitting the ENTER key at the question
:: will work.
echo %ans1%|findstr /r /c:"^[1-5]$" >nul
if errorlevel 1 (
  echo/ & echo At errorlevel 1. Wrong format used. Default is still: !ans1_Def! & echo/
  set "ans1=" && goto Q1
  ) else ( echo Correct format has been used. %ans1% is the one. && goto :Q2 )

:Q2
echo/
echo -----------------------------
echo/
echo Now at the next question
echo !ans1!
echo/
pause
exit