Re: [open-cobol-list] How to use RANDOM function.

[Michael]

It would be nice when you use FUNCTION RANDOM with (0), that the function would actually get a new seed from the system timer to start a new sequence of pseudo-random numbers. Currently as far as I know, calling FUNCTION RANDOM with the value 0, or calling it without passing an argument at all, always resets the sequence of pseudo-random numbers to the same starting point. 

The seed would a 16 or 32 bit integer?

Want truly random? Look at random.org where they get their numbers from random 
atmospheric noise.

Mike.

Vince Coen wrote:
> On Wednesday 10 Nov 2010, John Culleton wrote:
>   
> > I want to have a certain number randomly chosen every time a certain
> > program runs.
> >
> >  I have this in WORKING-STORAGE:
> >         77  RANDUM PICTURE S9V9(10).
> > I have this statement:
> > COMPUTE RANDUM = FUNCTION RANDOM(0).
> > Every time I run the program the value of RANDUM is the same. If I
> > change the seed then I get a different number but that is repetitious
> > also. If I leave off the seed it acts as if the seed was zero.
> >     
>
> I think you are misusing this function in regard to OC, form is:
>
> Function returns a numeric value that is a pseudo-random number from a 
> rectangular distribution. The type of this function is numeric.
>
> function random (argument-1)
>
> the returned value is grater than or equal to zero and less than 1. The domain 
> of arg-1 values will yield distinct sequences of pseudo random numbers.
> [So far so good]. 
> This subset includes the values from 0 through at least 32767.
>
> [Taken from MF manual but the OC docs does not specify this]
>
> 1. Try just doing move function random (0) to randum and see what you get.
>
> 2. Suggest you also try using a pic of 9(5) (without the implied decimal 
> placing and see what you get.  
>
> I'm saying this just in case OC does NOT stick to values 0 to 1.
>
>
> Vince
>
>
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