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ViolentAJ
Joined: 05 Feb 2009
Posts: 56
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 Posted: Fri Apr 17, 2009 6:38 pm Post subject: Random Integers |
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Sorry. I took a look at an example, but it didn't work. I just want to know how to get something along the lines of
Math.Random(100); which should give a random number between 0 and 99. Thanks.
I just need to know what to import (std.random, I assum) and how to use it. Sorry for being a n00b. Thanks.
I'm working on a rudimentary text-based RPG. |
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michaelp
Joined: 27 Jul 2008
Posts: 114
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ViolentAJ
Joined: 05 Feb 2009
Posts: 56
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| Posted: Fri Apr 17, 2009 11:21 pm Post subject: |
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| Michael, I tried to click the replies to that linkt hat you gave me, but they lead to some other thread... |
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michaelp
Joined: 27 Jul 2008
Posts: 114
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| Posted: Sat Apr 18, 2009 6:58 am Post subject: |
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Gee, the same thing happens to me. 
Here are the replies:
Jarrett Billingsley:
| Quote: | lo + rand() % (hi - lo)
assuming you're using Phobos, where rand() returns a number in the
range [0, uint.max].
This will get you a number in the range [1000, 2000); that is, it will
be at least 1000 and at most 1999. If you need 2000 to be one of the
numbers generated, use 2001 as the hi. |
Don:
| Quote: | The random numbers will not be evenly distributed, though. You'll get
more which are closer to 1000 than to 2000.
(Imagine uint.max = 1000. Then 0 and 1000 map to 1000, but every other
number has only one number which maps to it).
Simple way to fix this is to ignore numbers from the non-uniform part:
uint rmax = uint.max - (uint.max % (hi-lo));
uint r;
do {
r = rand();
} while (r>rmax);
return lo + r % (hi - lo); |
Hope that helps. |
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ViolentAJ
Joined: 05 Feb 2009
Posts: 56
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| Posted: Sat Apr 18, 2009 6:53 pm Post subject: |
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Thanks. I think that the way to do it in C is much easier to understand though. The only problem is I get the following error.
This is my code:
| Code: |
//Random number generation. This is an important concept for game design.
//There is no easy Math.Random() or Random class like in Java or ActionScript.
module RandomNumberTest;
import std.stdio;
//We can import from the C standard library too
import std.c.stdlib;
import std.c.time;
void main(string[] args){
//Seed the randomizer so that we get different values
srand(time(NULL));
//Generate the number
int number = rand();
writefln(number);
}
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This is the error:
| Code: |
C:\WorkingInD\Test\RandomNumberTest.d(15): Error: undefined identifier NULL
C:\WorkingInD\Test\RandomNumberTest.d(15): function std.c.time.time (int*) does not match parameter types (int)
C:\WorkingInD\Test\RandomNumberTest.d(15): Error: cannot implicitly convert expression (NULL) of type int to int*
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Of course, I'm used to just calling Random in Java or Flash ActionScript.
Sadly, I cannot use the Tango library. Last time I tried to install it it destroyed everything. It also ruined my setup in Eclipse. |
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ViolentAJ
Joined: 05 Feb 2009
Posts: 56
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| Posted: Sat Apr 18, 2009 7:01 pm Post subject: |
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| Nevermind. I just had to use null instead of NUL with all caps. Problem solved for now lol thanks for your help. |
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michaelp
Joined: 27 Jul 2008
Posts: 114
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ViolentAJ
Joined: 05 Feb 2009
Posts: 56
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| Posted: Sun Apr 19, 2009 4:22 pm Post subject: |
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| I used C's srand() and rand(). It was a bit easier for me to understand. |
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