public static long randomNumber(int min, int max) {
return Math.round((Math.random() * (max - min)) + min);
}
The title sais it: you'll get a random number within a given min and max.
2007-10-01T00:50:20+00:00
35
Java
get-a-random-number-within-a-given-interval
10
Get a random number within a given interval
2009-08-18T08:48:25+00:00
93
public static int randomNumber(int min, int max) {
return min + (int)(Math.random() * (max - min));
}
35
Why do you return a 'long', if the range is only specified by ints? The result always fits in an integer.
This is more or less the standard method for generating a random number. The only (usefull) change I can think of is:
2007-10-01T05:35:36+00:00
146
Java
3
1
On Get a random number within a given interval
84
typefreak
public static long randomNumber(int min, int max) {
int number = new Random().nextInt(++max);
return number < min ? number += min : number;
}
35
Try to use MTRandom ("A very fast random number generator"):
http://www.koders.com/java/fid0498E2527646FD994A3DC7288DC13144CC0EA8FF.aspx
http://goui.net/doc/net/goui/util/MTRandom.html
http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
2007-10-01T10:55:06+00:00
158
Java
1
1
On Get a random number within a given interval
Carlos Daniel de Mattos Mercer
http://www.useinet.com.br
private static int randomNumber(int min, int max) {
int number = new Random().nextInt(++max);
return number < min ? number += min : number;
}
35
2007-10-01T10:59:12+00:00
159
Java
1
1
On Get a random number within a given interval
private int
public static int randomNumber(int min, int max) {
int number = new Random().nextInt(++max);
return number < min ? number += min : number;
}
35
2007-10-01T11:22:31+00:00
161
Java
1
1
On Get a random number within a given interval
public
public static int randomNumber(int min, int max) {
int number = new Random().nextInt(++max);
return number < min ? number += min : number;
}
35
This method will fail when the difference between min and max is smaller then a random number that is generated that is less then min.
(Min = 20, Max = 21, Number = 5)
2007-10-01T11:59:34+00:00
165
Java
1
1
On Get a random number within a given interval
Cameron Hatfield
public static int randomNumber(int min, int max) {
return min + (new Random()).nextInt(max-min);
}
35
The original implementation is awful. Passed min 0 and max 2, it has about a 25% chance of returning 0, 50% chance of returning 1, and 25% chance of returning 2.
Passing through a double or doing rounding only introduces potential for blatant or subtle nonuniformity. Also, it would be wise to follow the underlying Java API's convention of being inclusive of the min value, exclusive of the max value.
The following does the right things.
If this were a performance critical operation you might cache the Random instance in a static field. If you wanted reproducible 'random' series (as in simulations) you would cache a Random instance that was created with a client-contributed seed value. If you needed very high-quality (pseudo)randomness you would use SecureRandom instead, perhaps with a non-default algorithm/provider package.
2007-10-01T16:00:39+00:00
173
Java
5
2
On Get a random number within a given interval
Gordon Mohr
http://gojomo.blogspot.com
public static int myRandom (int min, int max)
{
return min + (int)Math.round((Math.random() * (max - min)));
}
35
What Gordon posted will fail with for example inputs of 0 and 1. Mine wont.
2009-01-18T00:53:16+00:00
143794
Java
0
0
On Get a random number within a given interval
Ben
-