Java Math.random()

 class Main { public static void main(String[] args) { 
 // generates a random number between 0 to 1 System.out.println(Math.random()); 
 } } // Output: 0.3034966869965544

Syntax of Math.random()

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 satisfies some condition of randomness. Hence called pseudo random 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.random() 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,

Also Read:

• Math.round()
• Math.pow()
• Math.sqrt()