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Pascal and Delphi Discussion Thread
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Nov 10th, 2007

help with random numbers in pascal

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I need a program that generates a nxn matrix with random numbers, but they're not completely random. They must be delimited in -20,0 < x < 20,0, for example, but all i searched for the Random functions in pascal says that it produce numbers in a interval starting in zero...so, i would like to know how do i generate random numbers in a -n < x < n interval.

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pukepuke

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Nov 10th, 2007

Re: help with random numbers in pascal

If you don't want the same random numbers over and over again, at the very beginning of your program, call the randomize procedure.

Delphi Syntax (Toggle Plain Text)
begin
  randomize;  // init number generator from system clock
  ...
end.
begin
  randomize;  // init number generator from system clock
  ...
end.

As for the range, the problem is purely mathematical. If you have a list of seven numbers (0, 1, 2, 3, 4, 5, 6), what do you have to do to it to make it (-3, -2, -1, 0, 1, 2, 3)?

Hope this helps.

Last edited by Duoas; Nov 10th, 2007 at 11:12 am.

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Nov 10th, 2007

Re: help with random numbers in pascal

I thought about this, just would like to know if there was a specific command for what I need. Thank you very much.

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Re: help with random numbers in pascal

No, the only function is random. If you say
x = random( 7 );

then x will be one of (0, 1, 2, 3, 4, 5, 6).

Duoas

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Nov 12th, 2007

Re: help with random numbers in pascal

This program will generate a random number between -20 and 20.

(Toggle Plain Text)

program RandomX;

var x : Integer;

begin

       Randomize;
       x := (Random(40)-20);     // -20 <= x < 20
 
end.

Hoped this helped.

~ Artmann

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