SQRT

@echo off
setlocal enabledelayedexpansion

:sqrt
set toparse=0
set answer=

set partpartans=0
set partans=
set part=0
set adder=00

set operation=00

set precision=0

cls
echo _______________________
echo.
echo Square Root Calculator
echo _______________________
echo.
set/p toparse=" Enter number: "
set/p precision=" Enter precision: "

call :StrLen toparse lengthh
set /a "length=%lengthh%-1"
set number=
set decimal=no
for /l %%l in (0,1,%length%) do (
    set now=!toparse:~%%l,1!
    if not !now!==. set number=!number!!now!
    if !now!==. (
        set/a "decimal=(%%l+1)/2"
        set/a "decimalpos=%%l+1"
    )
)
set newlen=%length%
if not %decimal%==no set/a newlen=%length%-1
if %decimal%==no set/a decimalpos="%lengthh%+1"
if %decimal%==no set/a decimal=(%lengthh%+1)/2
set/a septest=%decimalpos%-1
set/a sepmod="!septest! %% 2"
set sepstart=0
if %sepmod%==1 (
    set sepstart=1
    set cut1=!number:~0,1!
)
for /l %%c in (%sepstart%,2,%newlen%) do (
    set now=!number:~%%c,2!
    set/a nowcut=%%c+1
    set cut!nowcut!=!now!
)
call :StrLen cut!nowcut! multip
if %multip%==1 set/a cut!nowcut!="cut!nowcut!*10"

for /l %%p in (1,1,!precision!) do (
    if %%p leq !nowcut! set operation=!cut%%p!
    if not %%p leq !nowcut! set operation=00
    set/a "pminus=%%p-1"
    if "!decimal!"=="!pminus!" set answer=!answer!.
    if %%p==1 set/a "subtracted=!operation!"
    for /l %%i in (0,1,9) do (
        set /a "part=20*!partpartans!*%%i+%%i*%%i"
        if !part! leq !subtracted! set partans=%%i
    )
    set/a "finalpart=20*%partpartans%*!partans!+!partans!*!partans!"
    echo - finalpart: !finalpart!
    set "answer=!answer!!partans!"
    set "partpartans=!partpartans!%partans%"
    if %%p==1 set "partpartans=!partans!"
    set/a pplus=%%p+1
    echo !pplus!
    if !pplus! leq !nowcut! call set adder=%%cut!pplus!%%
    if not !pplus! leq !nowcut! set "adder=0"
    echo adder: !adder!

    if !precision! geq 2 (
        if not %%p==!precision! (
            set/a subtracted="!subtracted!-!finalpart!"
            set/a subtracted="!subtracted!*100"
            set/a subtracted="!subtracted!+!adder!"
        )
    )
)
echo _______________________
echo.
echo  Answer: !answer!
echo _______________________
pause >nul

exit

:StrLen
setlocal disabledelayedexpansion
set len=0
if defined %~1 for /f "delims=:" %%n in (
  '"(cmd /v:on /c echo(!%~1!&echo()|findstr /o ^^"'
) do set /a "len=%%n-3"
endlocal & if "%~2" neq "" (set %~2=%len%) else echo %len%
exit /b