random number generator - How to determine a coin toss online?

random-number-generator

06
2014-04

Aram Kocharyan

What resources can I use if I'm trying to settle a coin flip online? Obviously, a coin toss app won't work if it only displays the result to me - the other party should also see it. And we can't meet up in person. Sharing screens came to mind, but I was wondering if there's some session sharing website that handles things like this.

Answers

Mason Heller

There's a site at http://flipfor.us/ that will allow you to flip a coin and it will email the result to you and your opponent. For a one-off, it's useful

I'd consider building a site that allows two users to log in and flip coins together, but I have way too many little projects already. :P

Lèse majesté

You could create a shared Google Docs spreadsheet and enter this into one of the cells:

=ROUND(RAND())

Or...

=IF(ROUND(RAND()), "Joe", "Sally")

Every time you save (or rather Google Docs autosaves), the random number generator will generate a new number. So to do a coin toss just type a random character into any (other) cell and hit enter. Both users will see the same result.

Some not so simple but more interesting solutions...

You could try generating 2 random stock symbols:

CONCATENATE(
  CHAR(RANDBETWEEN(65,90)),
  CHAR(RANDBETWEEN(65,90)),
  CHAR(RANDBETWEEN(65,90))
)

and use GoogleFinance(..., "price") to look up which is higher. Sort of a Wall Street high card draw...

However, do not combine both formulas in one cell, because this will cause an infinite loop: GoogleFinance() will fetch the stock price, changing the spreadsheet, causing the RANDBETWEEN() functions to recalculate, causing the stock symbol to be changed, causing GoogleFinance() to fetch a new value...

You can however, automate this process safely by using JavaScript (Google Apps Script) to generate the random letters.

You can also use Google Apps Script to track the number of times the random number generator has been run in the first solution to prevent cheating (or simply modify the formula to insert a neutral value as a simple binary counter).

Another solution would be to take a random word or string, add the CODE() value of each character, and select the least significant bit. If you're really paranoid, have one person pick the string, and have the other pick which bit position to use.

Related Answers

Sathya

There is a discussion here that you could adapt for your purposes.

@Echo Off
Setlocal EnableDelayedExpansion
Set _RNDLength=8
Set _Alphanumeric=ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789
Set _Str=%_Alphanumeric%987654321
:_LenLoop
IF NOT "%_Str:~18%"=="" SET _Str=%_Str:~9%& SET /A _Len+=9& GOTO :_LenLoop
SET _tmp=%_Str:~9,1%
SET /A _Len=_Len+_tmp
Set _count=0
SET _RndAlphaNum=
:_loop
Set /a _count+=1
SET _RND=%Random%
Set /A _RND=_RND%%%_Len%
SET _RndAlphaNum=!_RndAlphaNum!!_Alphanumeric:~%_RND%,1!
If !_count! lss %_RNDLength% goto _loop
Echo Random string is !_RndAlphaNum!

TheOutcaste expains the above:

I've modified it so you can easily specify the length, and add or remove characters without having to change any other part of the code.

For example, you might not want to use both 0 and O (zero and Uppercase O), or 1 and l (one and lowercase L).

You can use punctuation except for these characters:
! % ^ & < >
You can use ^ and %, but must enter them in the _Alphanumeric variable twice as ^^ or %%. However, if you want to use the result (_RndAlphaNum) later in the batch file (other than Echoing to the screen), they might require special handling.

You can even use a space, as long as it's not the last character in the string. If it ends up as the last character in the generated string though, it will not be used, so you would only have 7 characters.

Scott Chamberlain

here is mine. Ameture, but it works

@Echo OFF
@echo Would You Like Me To Make You A Password? Type Your Response And Press Enter.
set /p ans=
if %ans%==yes (goto yes
)
if %ans%==no (goto exit
)

:exit
cls
@echo Are You Sure?
set /p ans=
if %ans%==yes (goto exit
)
if %ans% NEQ yes (goto yes
)
:yes
cls 
@echo Loading...

@echo OFF
ping localhost -n 4 > Nul
goto hardpart





:hardpart
@echo OFF
cls
@echo Get a peice of paper so you will remember
pause
cls
@echo OFF
set /A r=%RANDOM% %% 25 + 1
cls
if %r%==1 goto 1
if %r%==2 goto 2
if %r%==3 goto 3
if %r%==4 goto 4
if %r%==5 goto 5
if %r%==6 goto 6
if %r%==7 goto 7
if %r%==8 goto 8
if %r%==9 goto 9
if %r%==10 goto 10
if %r%==11 goto 11
if %r%==12 goto 12
if %r%==13 goto 13
if %r%==14 goto 14
if %r%==15 goto 15
if %r%==16 goto 16
if %r%==17 goto 17
if %r%==18 goto 18
if %r%==19 goto 19
if %r%==20 goto 20
if %r%==21 goto 21
if %r%==22 goto 22
if %r%==23 goto 23
if %r%==24 goto 24
if %r%==25 goto 25
if %r%==26 goto 26
:1 
@echo 1st letter is a
goto number2
pause
goto number2
:2
@echo 1st letter is b
pause
goto number2
:3
@echo 1st letter is c
pause
goto number2
:4
@echo 1st letter is d
pause
goto number2
:5
@echo 1st letter is e
pause
goto number2
:6
@echo 1st letter is f
pause
goto number2
:7
@echo 1st letter is g
pause
goto number2
:8
@echo 1st letter is h
pause
goto number2
:9
@echo 1st letter is i
pause
goto number2
:10
@echo 1st letter is j
pause
goto number2
:11
@echo 1st letter is k
pause
goto number2
:12
@echo 1st letter is l
pause
goto number2
:13
@echo 1st letter is m
pause
goto number2
:14
@echo 1st letter is n
pause
goto number2
:15
@echo 1st letter is o
pause
goto number2
:16
@echo 1st letter is p
pause
goto number2
:17
@echo 1st letter is q
pause
goto number2
:18
@echo 1st letter is r
pause
goto number2
:19
@echo 1st letter is s
pause
goto number2
:20
@echo 1st letter is t
pause
goto number2
:21
@echo 1st letter is u
pause
goto number2
:22
@echo 1st letter is v
pause
goto number2
:23
@echo 1st letter is w
pause
goto number2
:24
@echo 1st letter is x
pause
goto number2
:25
@echo 1st letter is y
pause
goto number2
:26
@echo 1st letter is z
pause
goto number2
:number2
@echo OFF
set /A s=%RANDOM% %% 25 + 1
cls
if %s%==1 goto 1a
if %s%==2 goto 2a
if %s%==3 goto 3a
if %s%==4 goto 4a
if %s%==5 goto 5a
if %s%==6 goto 6a
if %s%==7 goto 7a
if %s%==8 goto 8a
if %s%==9 goto 9a
if %s%==10 goto 10a
if %s%==11 goto 11a
if %s%==12 goto 12a
if %s%==13 goto 13a
if %s%==14 goto 14a
if %s%==15 goto 15a
if %s%==16 goto 16a
if %s%==17 goto 17a
if %s%==18 goto 18a
if %s%==19 goto 19a
if %s%==20 goto 20a
if %s%==21 goto 21a
if %s%==22 goto 22a
if %s%==23 goto 23a
if %s%==24 goto 24a
if %s%==25 goto 25a
if %s%==26 goto 26a
:1a 
@echo The next letter is a
pause
goto number2
:2a
@echo The next letter is b
pause
goto number2
:3a
@echo The next letter is c
pause
goto number2
:4a
@echo The next letter is d
pause
goto number2
:5a
@echo The next letter is e
pause
goto number2
:6a
@echo The next letter is f
pause
goto number2
:7a
@echo The next letter is g
pause
goto number2
:8a
@echo The next letter is h
pause
goto number2
:9a
@echo The next letter is i
pause
goto number2
:10a
@echo The next letter is j
pause
goto number2
:11a
@echo The next letter is k
pause
goto number2
:12a
@echo The next letter is l
pause
goto number2
:13a
@echo The next letter is m
pause
goto number2
:14a
@echo The next letter is n
pause
goto number2
:15a
@echo The next letter is o
pause
goto number2
:16a
@echo The next letter is p
pause
goto number2
:17a
@echo The next letter is q
pause
goto number2
:18a
@echo The next letter is r
pause
goto number2
:19a
@echo The next letter is s
pause
goto number2
:20a
@echo The next letter is t
pause
goto number2
:21a
@echo The next letter is u
pause
goto number2
:22a
@echo The next letter is v
pause
goto number2
:23a
@echo The next letter is w
pause
goto number2
:24a
@echo The next letter is x
pause
goto number2
:25a
@echo The next letter is y
pause
goto number2
:26a
@echo The next letter is z
pause
goto number2

Scott Chamberlain

rem 16 stings pwd

setlocal ENABLEEXTENSIONS ENABLEDELAYEDEXPANSION
set alfanum=ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789

set pwd=
FOR /L %%b IN (0, 1, 16) DO (
SET /A rnd_num=!RANDOM! * 62 / 32768 + 1
for /F %%c in ('echo %%alfanum:~!rnd_num!^,1%%') do set pwd=!pwd!%%c
)

echo pwd=%pwd%

Tog

I edited pauls one:

@Echo Off
color 0a
set /P lengthnumberuser="What length do you want your password to be?   "
pause
cls
Setlocal EnableDelayedExpansion
Set _RNDLength=%lengthnumberuser%
Set _Alphanumeric=ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789
Set _Str=%_Alphanumeric%987654321
:_LenLoop
IF NOT "%_Str:~18%"=="" SET _Str=%_Str:~9%& SET /A _Len+=9& GOTO :_LenLoop
SET _tmp=%_Str:~9,1%
SET /A _Len=_Len+_tmp
Set _count=0
SET _RndAlphaNum=
:_loop
Set /a _count+=1
SET _RND=%Random%
Set /A _RND=_RND%%%_Len%
SET _RndAlphaNum=!_RndAlphaNum!!_Alphanumeric:~%_RND%,1!
If !_count! lss %_RNDLength% goto _loop
Echo Password is: is !_RndAlphaNum!

pause

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random number generator - How to determine a coin toss online?