I am working on a short batch file program that accepts input and does some simple math. It seems to work correctly for everything except the first echo. Here is the code:
set /p usercommand= "Input:"
if "%usercommand%" equ "done" (
set /p usertimeouthours= "Input Hours: "
echo (%usertimeouthours%)
set /p usertimeoutminutes= "Input Minutes: "
echo (%usertimeoutminutes%)
set /p usertimeoutseconds= "Input Seconds: "
echo (%usertimeoutseconds%)
set /a answer= %usertimeouthours%*3600+%usertimeoutminutes%*60+%usertimeoutseconds%
echo %answer%
goto end
) else (
echo finished
goto user
)
:end
why does the first echo only output
(
my guess is something is wrong with my if statement, does anyone know how I should change it?
Thanks!
Problem 1 – Normal vs Delayed expansion of variables
Normal expansion using
%var%occurs at parse time, and the entire IF statement is parsed all at once, including the contents within the parentheses. So something likeecho (%usertimeouthours%)displays the value of USERTIMEOUTHOURS as it existed before the IF statement was executed (before SET /P set the value).The fix is to enable delayed expansion at the top using
setlocal enableDelayedExpansionand use!var!instead of%var%. Delayed expansion occurs at execution time instead of parse time.Problem 2 – Unescaped special characters
There are a number of characters that have special meaning and must be either escaped with
^or quoted if you want the character to be treated as a string literal.One of the special characters is
). It will terminate any code block opened with(unless it is escaped or quoted. You need to escape that character as^)when you use it in your ECHO statements because those statements are within a parenthesized block of code.Simplification of your SET /A statement
You do not need to expand variables when used in a SET /A computation. You can simply use the variable name without enclosing in percents or exclamations. This convenience only works with SET /A.