random产生随机数字1到n

不念不忘少年蓝@ 2023-02-15 12:57 22阅读 0赞

*注意：nextInt(9)，产生的数字范围是0~8；*  
*因此，如果想输出0~9，应该nextInt(9)+1*  
**例子：**

package cn.itcast.day0601.demo03;
    
    import java.util.Random;
    import java.util.Scanner;
    
    public class Demo12Random {
        
        public static void main(String[] args) {
        
            System.out.println("你想弹出1到几：");
            int num = new Scanner(System.in).nextInt();
            Random r =new Random();
            int result = r.nextInt(num) + 1;
            //原本产生范围是0~num-1，如今为1~num
            System.out.println("产生的随机数是：" + result);
        }
    }

运行结果：  
![在这里插入图片描述][20200605172533883.png]  
**多来几组数据查看一下：**

package cn.itcast.day0601.demo03;
    
    import java.util.Random;
    import java.util.Scanner;
    
    public class Demo12Random {
        
        public static void main(String[] args) {
        
            System.out.println("你想弹出1到几：");
            int num = new Scanner(System.in).nextInt();
            Random r =new Random();
            for (int i = 0; i < 10; i++) {
        
                int result = r.nextInt(num) + 1;
                //原本产生范围是0~num-1，如今为1~num
                System.out.println("产生的随机数是：" + result);
            }
            
        }
    }

结果：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZpZ2h0aW5nX2RyZWFt_size_16_color_FFFFFF_t_70]

[20200605172533883.png]: https://img-blog.csdnimg.cn/20200605172533883.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZpZ2h0aW5nX2RyZWFt_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200605172643297.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZpZ2h0aW5nX2RyZWFt,size_16,color_FFFFFF,t_70