Java Math.random() – Examples

Java Math random()

random() returns a double value greater than or equal to 0 and less than 1.0.

Following is the syntax of random() method.

double n = random()

random() method uses the pseudo-random number generator function java.util.Random().

Example 1 – Math.random()

In the following example, we use random function to generate a random number in the range [0.0, 1.0).

Java Program

public class MathExample {
	public static void main(String[] args) {
		double n = Math.random();
		System.out.println(n);
	}
}

Output

0.8503998521780656

Example 2 – Math.random() – Generate Random Double from [min, max)

You can use random() method to generate a random number between a given minimum and a maximum.

In the following program, we will generate a random double number in the range [min, max).

Java Program

public class MathExample {
	public static void main(String[] args) {
		double min = 2.65;
		double max = 8.693;
		double n = min + (max-min)*Math.random();
		System.out.println(n);
	}
}

Output

4.723410184654693

Example 3 – Math.random() – Random Integer in [min, max)

If any of the base or height is infinite, then the length of hypotenuse is infinite, and random() returns positive infinite.

Java Program

public class MathExample {
	public static void main(String[] args) {
		int min = 20;
		int max = 80;
		int n = (int) (min + (max-min)*Math.random());
		System.out.println(n);
	}
}

Output

34

Conclusion

In this Java Tutorial, we learned about Java Math.random() function, with example programs.