Generating Random Numbers between a potentially negative range

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laura.paterson@gmail.com - 08 Feb 2006 11:50 GMT

Hi,

I have looked in the existing posts to try to find the solution to
this, but cannot find an answer...

I want to be able to create a random number within a certain range,
that may be partially or entirely negative, i.e. between 17 and 25, -17
and 25, -25 and 25... etc.

I have found various solutions using Math and Random, which would work
if both limits are either positive or negative, or if they are the same
distance form the origin, ie. -25, 25... but nothing that will work for
all range possibilities.

Any help will be much appreciated!
Thanks,
Laura

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Bart Cremers - 08 Feb 2006 12:01 GMT

public static int nextInt(int low, int high) {
if (low > high) {
int tmp = low;
low = high;
high = tmp;
}

int diff = high - low;

int i = rnd.nextInt(diff);

return i + low;
}

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Boris Stumm - 09 Feb 2006 09:04 GMT

> public static int nextInt(int low, int high) {
> if (low > high) {
[quoted text clipped - 9 lines]
> return i + low;
> }

How about:
import static java.lang.Math.*;

public static int nextInt(int low, int high) {
return min(low, high) + rnd.nextInt(abs(high - low));
}

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Roedy Green - 08 Feb 2006 17:53 GMT

>I want to be able to create a random number within a certain range,
>that may be partially or entirely negative, i.e. between 17 and 25, -17
>and 25, -25 and 25... etc

see http://mindprod.com/jgloss/pseudorandom.html#LOWHIGH

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Canadian Mind Products, Roedy Green.
http://mindprod.com Java custom programming, consulting and coaching.

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Generating Random Numbers between a potentially negative range

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