Created: 2023-09-02 09:44
Status: #concept
Subject: Programming
Tags: Java Java Class java.util
java.util.Random
An instance of this class is used to generate a stream of pseudorandom numbers.
Get a Random Value with next___()
First, we have to instantiate a
new Random() instance then use the instance.next___() methods to get a random Java Data Type value.
nextBoolean()nextDouble()between0.0and1.0,[0.0, 1.0]nextGaussian()is similar, but the values are normally distributed.
nextFloat()between0.0and1.0nextInt()randomint, unless we specifynextInt(bound)so it returns a value between0andbound - 1, denoted as[0, bound).nextLong()
Getting Random Negative Numbers
We can use the nextInt method to create diverse randomness. For example, we might need a program to give us a temperature between [-30,50]. We can do this by first creating random a number between 0 and 80 and then subtracting 30 from it.
We shift the range by
MIN to be within [0, MAX] then subtract the resulting number with MIN.
Random weatherMan = new Random();
int temperature = weatherMan.nextInt(81) - 30; // 81 because we want to include 80
System.out.println(temperature);