# Java Math.random()

The Java Math.random() method returns a random value that is greater than or equal to 0.0 and less than 1.0.

The syntax of the `random()` method is:

``Math.random()``

Note: The `random()` method is a static method. Hence, we can call the method directly using the class name `Math`.

## random() Parameters

The `Math.random()` method does not take any parameters.

## random() Return Values

• returns a pseudorandom value between 0.0 and 1.0

Note: The values returned are not truly random. Instead values are generated by a definite computational process, that satisfy some condition of randomness. Hence called pseudorandom values.

## Example 1: Java Math.random()

``````class Main {
public static void main(String[] args) {

// Math.random()
// first random value
System.out.println(Math.random());  // 0.45950063688194265

// second random value
System.out.println(Math.random());  // 0.3388581014886102

// third random value
System.out.println(Math.random());  // 0.8002849308960158

}
}``````

In the above example, we can see that the random() method returns three different values.

## Example 2: Generate Random Number Between 10 and 20

``````class Main {
public static void main(String[] args) {

int upperBound = 20;
int lowerBound = 10;

// upperBound 20 will also be included
int range = (upperBound - lowerBound) + 1;

System.out.println("Random Numbers between 10 and 20:");

for (int i = 0; i < 10; i ++) {

// generate random number
// (int) convert double value to int
// Math.round() generate value between 0.0 and 1.0
int random = (int)(Math.random() * range) + lowerBound;
System.out.print(random + ", ");
}

}
}``````

Output

```Random Numbers between 10 and 20:
15, 13, 11, 17, 20, 11, 17, 20, 14, 14,```

## Example 3: Access Random Array Elements

``````class Main {
public static void main(String[] args) {

// create an array
int[] array = {34, 12, 44, 9, 67, 77, 98, 111};

int lowerBound = 0;
int upperBound = array.length;

// array.length will excluded
int range = upperBound - lowerBound;

System.out.println("Random Array Elements:");
// access 5 random array elements
for (int i = 0; i <= 5; i ++) {

// get random array index
int random = (int)(Math.random() * range) + lowerBound;
System.out.print(array[random] + ", ");
}

}
}``````

Output

```Random Array Elements:
67, 34, 77, 34, 12, 77,```