％〜1在此批处理文件中做什么？

我找到了这段代码，但是有些部分我不理解。

这是我的代码：

Main.bat：

@echo off
set "CallCount=0"
set "Mood="
set /P "Mood=Your mood is: "
call Receive.bat "%Mood%"
rem *Random stuff*
set "Food="
set /P "Food=The food you want is: "
call Receive.bat "%Food%"
set "CallCount="

Receive.bat：

@echo off  
set /A CallCount+=1           
if "CallCount"=="2" goto Call2   
if not "%~1"=="" echo %1     <----
*Random Stuff*                   |
goto :EOF                        |---What is %~1 doing in this area?
:Call2                           |
if not "%~1"=="" echo %1     <----
rem Commands for second call.

编辑：这是一个使用call命令两次的文件。