C++如何解决rand()函数生成的随机数每次都一样的问题

#include <iostream>
#include <time.h>
using namespace std;
int main()
{
	srand((unsigned)time(NULL));
	int n = rand() % 100;
	cout << n << endl; 
}

#include<iostream>
#include<cstdio>
#include<stdlib.h>
#include<time.h>
using namespace std;
int main()
{
	/* 
	甲   乙    丙    丁   
甲   -    0.1  0.3   0.5
乙  0.9   -    0.7   0.4 
丙  0.7  0.3   -     0.2
丁  0.5  0.6  0.8    -
*/
	int randf;
	long long int win=0;
	srand(time(0));
	for(int i=1;i<=100000;i++)
	{
		randf=rand();
		if(randf%3==0)//ab
		{
			if(randf%10<1){//a win b
				if(randf%10<2){//c win d
					if(randf%10<3)win++;
				}
				else{//d win c
					if(randf%10<5)win++;
				}
			}
		}
		else if(randf%3==1)//ac
		{
			if(randf%10<3)//a win c
			{
				if(randf%10<4)//b win d
				{
					if(randf%10<1)win++;
				}
				else//d win b
				{
					if(randf%10<5)win++;
				}
			}
		}
		else  //ad
		{
			if(randf%10<5)//a win d
			{
				if(randf%10<3)//c win b
				{
					if(randf%10<3)win++;
				}
				else//b win c
				{
					if(randf%10<1)win++;
				}
			}
		}
	}
	printf("%f\n",win/100000.0);
	return 0;
}