collatzConjecture.bat

REM Defines the variables 'change' and 'count'
@echo off
cls
set /a change=0
set /a count=0

REM Asks for input. The script will loop back
REM to this part in later sections of the code.
:loop
set /p "input=Input a number: "
set /a change=input
goto :skip

REM Sets the variable 'input' to the same value
REM as 'change'.
:numtest
if %change%==0 (
goto :skip
)
set /a input=change

:skip
set /a count=count+1
set /a "number=%input%" 2>nul

REM Makes sure that the number is valid.
if "%input%" NEQ "%number%" (
cls
Echo Please enter a valid number! &Echo.&Echo.
goto :loop
)
Set /a Even=number%%2

REM Mathematical equations depending on whether
REM the input was even or odd.
if %Even% EQU 0 (
set /a answer=number/2
) else (
set /a answer=number*3
set /a answer=answer+1
)
if %answer%==1 (
goto :print
) else (
goto :check
)

REM Prints the number that you input at the start, and
REM the number of calculations made.
:print
echo Your input (%change%) returned as 1.
echo A total of (%count%) calculations were made.
set /a change=change+1
set /a count=0
pause
Echo.
goto :numtest

REM Sets 'input' to the value of 'answer' and repeats
REM the calculations over and over until 'answer' is 1.
:check
set /a input=answer
goto :skip