:factorial 要阶乘的数 输出变量
setlocal enabledelayedexpansion
set res=1&set var=%~1
for /l %%i in (!var! -1 1) do Call :cen !res! %%i res
Endlocal&set %~2=%res%&goto :eof
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:C 组合数下标 组合数上标 输出变量
setlocal enabledelayedexpansion
set /a "u=1,d=1"&set m=%~1&set n=%~2&set /a sp=!n!+1
for /l %%i in (!m! -1 !sp!) do set t1=%%i&Call :cen !t1! !u! u
for /l %%i in (!n! -1 1) do set t2=%%i&Call :cen !t2! !d! d
set /a ret=!u!/!d!
Endlocal&set %~3=%ret%&goto :eof
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