In this article, we will explain Math.random method in Java through examples.
Java provides us
Math class, which includes methods with basic numeric operations such as logarithm, square root, etc. One of these methods is
random(), which gives us a pseudorandom positive double number greater than or equal to 0.0 and less than 1.0 – [0.0, 1.0).
You can learn more through our Java Math Operators and Math Class Tutorial.
In this example, we are going to show how to produce integer and double random numbers between a defined space, via math.random method in Java.
1. Example of Math.random method in Java
Create a java class with name MathRandom Class and paste the following code.
Now lets explain the code above.
Firstly, we use Java math.random method in order to take a positive signed double value, that belongs to the range [0.0, 0.1). For generating random integer or double numbers between a range, we should multiply and/or sum the appropriate positive and/or negative values in order to achieve the desired result. For example, if we want a random positive, double number greater than or equal to 0.0 but less than 20.0, we should multiply the result of
random() method with the double number 20.0. Respectively, if we multiply the result with 5 and add number 3, the range has a minimum value number 3 and as maximum value their sum (5+3). Please notice that the random values are always less than this sum – in our example the range is [3,8). Also notice that for integer values we should cast the result. We can use the same way for negative random numbers etc.
For a better understanding, please look the output of the execution. As you can notice, all the parameters take a value that is into their respective range.
Double between 0.0 and 1.0: x = 0.9749288905833321 Double between 0.0 and 20.0: y = 14.067387697238761 Integer between 3 and 8: r1 = 7 Integer between -10 and 10: r2 = -9
You can learn more about the math.random method in Java in our Java random number generator Example.
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- Java random number generator Example
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- Java Tutorial for Beginners
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3. Download the Source Code
This was a tutorial about Math.random method in Java.
Download the source code of this example: Math.random Java Example
Last updated on March 2nd, 2022