@echo off
set MAX=2147483647
:begin
cls
set /p n=输入待开方数（1~%MAX%）：
set a=2
set r=
:int_part
  set /a old_a=a,a=(n/a+a)/2
  if %old_a% lss %a% goto int_part
  set /a delta=old_a-a
  if %delta% gtr 1 goto int_part
::prepare
  set /a near_n=a*a
  if %near_n% equ %n% goto end
  set /a t=n-near_n,u=a
:dec_part
  set /a t*=100,d=10,tol_d=MAX/(u*20)
  if %tol_d% lss 9 goto end
  if %t% lss 0 goto end
  :try_d
    set /a d-=1,v=d*(d+u*20)
    if %v% gtr %t% goto try_d
  set /a t-=v,u=u*10+d
  set r=%r%%d%
goto dec_part
:end
if "%r%" neq "" set a=%a%.%r%
echo 结果：%a%
pause>nul
goto begin
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@echo off
setlocal enabledelayedexpansion
title 开平方
echo 请输入需要开平方的数字:
set a=2
set comp=99999
set /p k=
for /l %%i in (1,1,9) do (
if "!k:~%%i,1!" == "" (
set len=%%i
goto begin
))
:begin
set /a t=len%%2
if not %t% equ 0 set /a len+=1
set /a len=len/2
:acr
set /a a=(k/a+a)/2
set /a m=a*a
set /a t=a-!comp:~0,%len%!
if %m% gtr %k% goto acr
if %m:-=% neq %m% goto acr
if %t% gtr 0 goto acr
set /a r=(k-m)*5000/a
set r=0000%r%
echo 结果：%a%.%r:~-4,-1%
pause>nul
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