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Introduction to the Random class
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The Random class is specially used to generate a pseudo-random Number, it has two constructors: one constructor uses the default seed (using the current time as the seed), and the other constructor requires the programmer to explicitly pass in a long integer seed.
The Random class provides more ways to generate various pseudo-random numbers than the random() method of the Math class. It can generate pseudo-random numbers of floating point type, pseudo-random numbers of integer type, and You can specify the range within which random numbers are generated.
Constructor:
public Random() //int范围内的随机数 public Random(long seed)
Code implementation:
1. Generate a random number.
import java.util.Random; public class Test01 { public static void main(String[] args) { // 创建随机数对象 Random random = new Random(); // 随机产生一个int范围内的数字 int num1 = random.nextInt(); System.out.println(num1); // 范围为[Integer.MIN_VALUE, Integer.MAX_VALUE]之间的一个整数 // 如果我要产生[0, 100]之间的整数怎么办 int num2 = random.nextInt(101); System.out.println(num2); // [0, 100]内的一个整数 // 注意:nextInt(101)翻译为,下一个int类型的数据是101,表示只能取到100 } }
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2. Generate a random number between [-100, 100]
public class Test02 { public static void main(String[] args) { // 创建随机数对象 Random random = new Random(); // 打印一千个 for (int i = 0; i < 1000; i++) { // 随机控制正负号,-1的0次方为1,-1的1次方为-1 int fuhao = random.nextInt(2); // 0或1 fuhao = (fuhao == 0) ? 1 : -1; int num3 = random.nextInt(101) * fuhao; System.out.println(num3); } } }
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