如何生成100万个无序不重复随机值

采取的方法如下代码：

#include 
#define NUM		1000000
void swap(int* pa,int* pb)
{
	int temp = 0;
	temp = *pa;
	*pa = *pb;
	*pb = temp;
}
int main(void)
{
	FILE *fp = NULL;
	unsigned i  = 0,index = 0;
	int *p = NULL;
	//创建文件
	if (NULL == (fp = fopen("d:\\b.txt","wb+")))
	{
		printf("ERROR!\n");
		getch();
		exit(1);
	}
	//开辟空间
	p = (unsigned *)malloc(sizeof(int)*NUM);
	//赋值 0 ~ NUM
	for (i = 0;i < NUM;i ++)
	{
		*(p + i) = i;
	}
	//洗牌
	srand((unsigned)time(NULL));
	for (i = 0;i < NUM;i ++)
	{
		index = rand()%NUM;
		swap(p+i,p+index);
	}
	//写入
	fseek(fp,0,SEEK_SET);
	for (i = 0;i < NUM;i ++)
	{
		fwrite(p+i,sizeof(unsigned),1,fp);
	}
	//关闭文件
	fclose(fp);
	getch();
	return 0;
}

方法也很简单，在此不多说了，仅供交流，不足之处，请高手多多指教。