Java创建随机数的四种方式总结

#include <stdio.h>

int main(void) {

	int left,right;
	printf("请输入一个数:");
	scanf_s("%d%d",&left,&right);
	//srand((unsigned)time(NULL));
	//for(int i = 0; i<10; i++)
	//printf("%d\n",rand() % one);
	

	//改进
	for (int i = 0; i < 10; i++)
	printf("随机值如下:%d\n", srandNext(left, right));

	return 0;
}

/********************************************************************************
* @Function: srandNext
* @Description:Find a random integer from min to max
* @Author: caiziqi
* @Version: 1.1
* @formal parameter:min : is the minimum value of the value range of this random number function, max: is the maximum value range of this random number function
* @Date: 2022-7-26
* @Return : returns a random integer
********************************************************************************/

int srandNext(int max,int min) {

	//To prevent users from passing parameters incorrectly
	if (max <= min) {
		if (max == min) {
			return max;
		}
		int temp = max;
		max = min;
		min = temp;
	}

	unsigned int static seed = 0;
	seed++;

	srand((unsigned)time(NULL) + seed * seed);

	return rand() % (max - min + 1) + min;
}

Random ra = new Random();
int right = (Math.max(a,b)) ;
int left = (Math.min(a,b);

int nu = (ra.nextInt(right) + left );

SecureRandom sra = new SecureRandom();
int right = (Math.max(a,b)) ;
int left = (Math.min(a,b);

int nu = (sra .nextInt(right) + left );

ThreadLocalRandom tra = ThreadLocalRandom.current();

int right = (Math.max(a,b)) ;
int left = (Math.min(a,b);

int nu = (tra .nextInt(right) + left );

int number = (int)(a + Math.random()*(b-a+1)) //返回一个int类型的参数 所以用 int 接收

import java.security.SecureRandom;
import java.util.Random;
import java.util.Scanner;
import java.util.concurrent.ThreadLocalRandom;

public class FourWaysOfRandomNumbers {
    public static void main(String[] args) {
        //用户输入两个数, 然后程序取这两个数里面的其中随机一个数
        Scanner input =  new Scanner(System.in);
        System.out.print("请输入两个数:");
        int a = input.nextInt();
        int b = input.nextInt();

        // 取值范围   left 最小值    right 最大值
        int right = Math.max(a,b);
        int left = Math.min(a,b);
        int nu;

        //四种生成随机数的方法

        //第一种
        Random ra = new Random();
             while( true){
            nu =(ra.nextInt(right) + left ) ;
            System.out.println(nu);

            //找到最大随机整数 输出并结束
            if(nu == right) {

                System.out.println(nu);
                return;
            }
        }

        //第二种
/*
        SecureRandom sra = new SecureRandom();

        while(true){
            nu =(sra.nextInt(right) + left ) ;
            System.out.println(nu);

            //找到最大随机整数 输出并结束
            if(nu == right) {
                System.out.println(nu);
                return;
            }
        }*/


        //第三种  在多线程的时候使用 是最佳的; 因为它会为每个线程都 使用不同的种子
       /* ThreadLocalRandom tra =  ThreadLocalRandom.current();
        while(true){
            nu =(tra.nextInt(right) + left ) ;
            System.out.println(nu);

            //找到最大随机整数 输出并结束
            if(nu == right) {
                System.out.println(nu);
                return;
            }
        }*/

      /*  //第四种
         int value = (int)(a + Math.random()*(b-a+1));
        System.out.println(value);
*/


    }

}