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We have already seen random number generator in java.In this post, we will address specific query on how to generate random number between 1 to 10.
Using random.nextInt() to generate random number between 1 and 10
We can simply use Random class’s nextInt() method to achieve this.
As the documentation says, this method call returns "a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified value (exclusive)", so this means if you call nextInt(10), it will generate random numbers from 0 to 9 and that’s the reason you need to add 1 to it.
Here is generic formula to generate random number in the range.
In our case,
minimum = 1
maximum = 10so it will be
randomGenerator.nextInt((10 – 1) + 1) + 1
randomGenerator.nextInt(10) + 1
So here is the program to generate random number between 1 and 10 in java.
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package org.arpit.java2blog; import java.util.Random; public class GenerateRandomInRangeMain { public static void main(String[] args) { System.out.println("============================"); System.out.println("Generating 10 random integer in range of 1 to 10 using Random"); System.out.println("============================"); Random randomGenerator=new Random(); for (int i = 0; i < 10; i++) { System.out.println(randomGenerator.nextInt(10) + 1); } } } |
When you run above program, you will get below output:
Generating 10 random integer in range of 1 to 10 using Random
==============================
1
9
5
10
2
3
2
5
8
1
Using Math.random() to generate random number between 1 and 10
You can also use Math.random() method to random number between 1 and 10. You can iterate from min to max and use Math.ran
Here is formula for the same:
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int randomNumber = (int) (Math.random()*(max-min)) + min; |
Let’s see with the help of example:
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public class MathRandomExample { public static void main(String[] args) { int min = 1; int max = 10; System.out.println("============================"); System.out.println("Generating 10 random integer in range of 1 to 10 using Math.random"); System.out.println("============================"); for(int i = 0; i < 5; i++) { int randomNumber = (int) (Math.random()*(max-min)) + min; System.out.println(randomNumber); } } } |
Generating 10 random integer in range of 1 to 10 using Math.random
============================
9
6
5
6
2
Using ThreadLocalRandom.current.nextInt() to generate random number between 1 and 10
If you want to generate random number in current thread, you can use ThreadLocalRandom.current.nextInt() to generate random number between 1 and 10.
ThreadLocalRandom was introducted in JDK 7 for managing multiple threads.
Let’s see with the help of example:
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import java.util.concurrent.ThreadLocalRandom; public class ThreadLocalRandomNextIntMain { public static void main(String[] args) { int min = 1; int max = 10; System.out.println("============================"); System.out.println("Generating 10 random integer in range of 1 to 10 using Math.random"); System.out.println("============================"); for(int i = 0; i < 5; i++) { int randomNumber = ThreadLocalRandom.current().nextInt(min, max) + min; System.out.println(randomNumber); } } } |
Generating 10 random integer in range of 1 to 10 using Math.random
============================
7
7
4
10
4
That’s all about java random number between 1 and 10.
