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This article mainly explains the "Java how to generate random integers in the specified range", the content of the article is simple and clear, easy to learn and understand, the following please follow the editor's ideas slowly in depth, together to study and learn "Java how to generate random integers in the specified range" bar!

1. Java.Math.random ()

When it comes to randomness, Math.random () comes to mind in many people's minds. Instead of generating an integer directly, it generates a decimal of type double between [0.0,1.0), as follows:

Public class demo01 {public static void main (String [] args) {System.out.println (Math.random ()); System.out.println (getType (Math.random ();} public static String getType (Object obj) {return obj.getClass () .toString ();}}

Print the results:

0.9567296616768681

Class java.lang.Double

Thus, this method can only generate a random double type decimal between [0. 0. 0. 0. 0. 0). So how to use the random method to generate random decimals within a specified range?

Suppose we need to generate a random integer in the range of [1 # 10]. The specific idea is as follows.

Math.random () = > [0.0,1.0) Math.random () * 10 = = > [0.0,10.0) (int) (Math.random () * 10) = = > [0,9] (int) (Math.random () * 10) + 1 = = > [1,10] for (int I = 0; I

< 10; i++) { int a=(int)(Math.random() * 10 )+1; System.out.println(a);} 最后打印结果（多次结果）： 9 10 1 10 3 1 6 8 7 5 可见结果符合我们的要求。 2.Java.util.Random.nextInt()；Random random=new Random();int a=random.nextInt(25); // 在[0, 25)之间随机生成一个 int 类型整数 假设我们需要生成一个 [63, 99]之间的整数，具体实现思路如下： [63, 99] ===>

First find the maximum common multiple of these two numbers = = > 9 [7,11] * 9 = = > take the minimum value 0 ([0,4] + 7) * 9

Random random=new Random (); for (int I = 0; I < 10; iTunes +) {int a = (random.nextInt (5) + 7) * 9; System.out.println (a);}

Print the results:

seventy-two

eighty-one

ninety-nine

ninety

sixty-three

ninety-nine

sixty-three

seventy-two

eighty-one

ninety-nine

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