Creating a random integer between two random boundaries

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Generating random number in a range with Java

I am trying to create a random number that is above the value of one boundary, and below another. The number can be equal to either of the boundaries too.

Both boundaries are created from random. highNumber is a random between 0 and 100, and lowNumber is a random between 0 and half of highNumber.

At the moment my code is as follows:

    public static void createCorrectNumber() {
            random = new Random();
            correctNumber = random.nextInt(highNumber)+1;
            correctNumber -= lowNumber;
    }

This is not functional, as when the lower bound is taken away from it, it can become lower than the boundary. Any ideas?

I should also mention both boundaries are created from random. highNumber is a random between 0 and 100, and lowNumber is a random between 0 and half of highNumber. — JamoBox, Dec 29 '12 at 12:09
what about http://stackoverflow.com/questions/363681/generating-random-number-in-a-range-with-java isnt this the same question?? — wmax, Dec 29 '12 at 12:12

score 4 · Accepted Answer · answered Dec 29 '12 at 12:11

4

use

correctNumber = random.nextInt(highNumber - lowNumber + 1) + lowNumber;

answered Dec 29 '12 at 12:11

Henry

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To be `highNumber` inclusive, you need to `+ 2` – Peter Lawrey Dec 29 '12 at 12:16
1

@PeterLawrey No, for example for low=0, high=2 the random number is in [0,3) so 2 is a valid result – Henry Dec 29 '12 at 12:18
"The number can be equal to either of the boundaries", to be `[0, 2]` you need to perform a `[0, 3)` with integers. – Peter Lawrey Dec 29 '12 at 12:20

Creating a random integer between two random boundaries

1 Answers1