会“批处理”（.bat）的来一下

set TodayYear=%date:~0,4%
set TodayMon=%date:~5,2%
set TodayDay=%date:~8,2%
echo %TodayDay%
pause
set LastdayYear=
set LastdayMon=
set LastdayDay=
set LastdayYear=%TodayYear%
set LastdayMon=%TodayMon%
set /A LastdayDay=TodayDay-1
echo %LastdayDay%
pause

为什么我1日岛7日，都显示正常，今天开始最后一个变成了-1，把电脑时间调成9月9日夜市-1,调成9月10日，又正常了。

加一行就行了

@echo off
set TodayYear=%date:~0,4%
set TodayMon=%date:~5,2%
set TodayDay=%date:~8,2%
for %%a in (08 09) do if %TodayDay%==%%a set TodayDay=%date:~9,1%
echo %TodayDay%
pause
set LastdayYear=
set LastdayMon=
set LastdayDay=
set LastdayYear=%TodayYear%
set LastdayMon=%TodayMon%
set /A LastdayDay=TodayDay-1
echo %LastdayDay%
pause