import java.util.Random;
public class llq1{
public static void main(String[] args) {
Random r=new Random();
//随机生成一个整数,int范围
System.out.println(r.nextInt());
//生成[0,100]范围的整数
System.out.println(r.nextInt(100+1));
//生成[0,100)范围的整数
System.out.println(r.nextInt(100));
//生成[40,100]范围的整数
System.out.println(r.nextInt(100-40+1)+40);
//随机生成一个整数long范围
System.out.println(r.nextLong());
//随机生成[0,1.0)范围的float型小数
System.out.println(r.nextFloat());
//随机生成[0,1.0)范围的double型小数
System.out.println(r.nextDouble());
}//调用Math.Random()函数能够返回带正号的double值,取值范围为[0.0,1.0)
}
拓展::
生成[m,n]之间的随机数
import java.util.Random;
import java.util.Scanner;
public class RandomTest {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
int m = in.nextInt();
int n = in.nextInt();
Random random = new Random();
System.out.println(random.nextInt(n - m + 1) + m);
}
}