Calculating Pi (π) in CMD

I am well aware that there are more accurate ways to calculate π but my version was created without looking at anyone else's batch program. I calculated pi using the Nilakantha series. This series is an infinite sequence starting with three.

The sequence then continues by alternating between adding and subtracting the number 4 divided by 3 consecutive integers starting with 2. An example of this would be

3 + 4/(2*3*4) - 4/(4*5*6) + 4/(6*7*8) - 4/(8*9*10) … … …

If this pattern is carried out indefinitely, you would get the result of pi.

You will need CMD, notepad, and a working 'ctrl' + 'c' & 'v' keys.

@echo off

title pi

set /a pi=300000000

set /a dePart = 2

set Lnum=2

:frac

echo %pi%

if %pi% == 314159265 goto done

set /a de = %dePart% * (%depart% + 1) * (%depart% + 2)

set /a dePart = %dePart% + 2

call :loop%Lnum%

goto frac

::::::::::add and subtract

:loop1

set /a pi = %pi% - (400000000 / %de%)

set Lnum=2

exit /b

::::::::::increment the fraction

:loop2

set /a pi = %pi% + (400000000 / %de%)

set Lnum=1

exit /b

:done

echo Done! (kind of)

set /a pi = %pi% - 300000000

echo 3.%pi%

echo (slightly better)

pause> nul

Overall, I am very disappointed with this project. Being only able to calculate pi with the help of pi doesn't make the project seem real. I had to stop the pi calculator early in the program because batch doesn't do decimals making the program take longer and be less accurate. You can probable expect me to attempt to create another batch program to better calculate pi.

But while you are waiting, take a look at this Amazing batch program over how to calculate pi (over 100 numbers after the decimal!) --> https://www.instructables.com/Calculate-pi-with-batch-file/