Java random number between 1 and 100

In this post, you will learn different ways to find the random number between 1 and 100 using the Java programming language.

Such a type of logical question is generally asked in an interview or in competitive exams. This can be helpful to improve your logical programming skills and is helpful in game development and other logical application development.

In this article, we have used the following in-built Java packages or classes to get the random number between 1 and 100.

• Using random.nextInt() method
• Using Math.random() method
• Using ThreadLocalRandom.current.nextInt() method

Java generate random number using random.nextInt()

The java.util.Random package provides a Random class to generate multiple types of random numbers, whether it is an int or a float. The nextInt() method of Random class is used to get a pseudorandom, uniformly distributed int value between 0 and the specified value. The given example demonstrates how to generate the random number using this method.

import java.util.*;
public class GenerateRandomNo {
    public static void main(String args[])
    {
        // create random object
        Random ran = new Random();
  
        // get number between 0-99
        int num = ran.nextInt(100);
  
        System.out.println
        ("Random number between 0 and 100: " + num);
    }
}

Random number between 0 and 100: 20

Java generate random number using Math.random()

The Math.random() method returns a pseudorandom number of data type double. It is a static method of the Math class. We can use this method to generate the random number between the given min and max value. Here is the syntax-

int randomNumber = (int) (Math.random()*(max-min)) + min;

In the given example, we have used the Math.random() function to generate the random number between 1 to 100.

// Generating  random number
// range of 1 to 100 using Math.random

public class GenerateRandomNumbers
{
    public static void main(String[] args) {
        int min = 1;
        int max = 100;

        int randomNum = (int) (Math.random()*(max-min)) + min;
        System.out.println("Random number between 0 and 100: "+randomNum);
    }
}

Random number between 0 and 100: 61

Java generate random number using ThreadLocalRandom.current.nextInt()

The nextInt() method of Java ThreadLocalRandom class returns a pseudorandom int value. This method overrides the nextInt() in class Random. ThreadLocalRandom is used to generate random number typically for multi threading environment. Here is the syntax-

public int nextInt() 

This method returns a pseudorandom int value between zero and the specified bound. The given example generates random number between range 1 to 100 using the ThreadLocalRandom.current.nextInt() method.

// Generating random number
// range from 1 to 100 using ThreadLocalRandom

import java.util.concurrent.ThreadLocalRandom;
public class GenerateRandomNumbers
{
    public static void main(String[] args) {
        int min = 1;
        int max = 100;
        int randomNumber =  ThreadLocalRandom.current().nextInt(min, max) + min;
        System.out.println("Random Numbers: " +randomNumber);
    }
}

Random Numbers: 99

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