Figure guessing game

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
int rander()// Generate random numbers 
{
	time_t ts;
	unsigned int n = time(&ts);// Acquisition time 
	srand(n);// Initialize random seed 
	int num = rand() % 100 + 1;// Random number range 1—100
	return num;
}	
int main()
{
	int a = -1;
	char opt = 'a';// choice 
	printf(" Please choose whether to start the game ：Y（y）/N(n)\n");
	scanf_s("%c", &opt,1);
	while (opt == 'Y' || opt == 'y')
	{
		int num = rander();
		int tmp = 0;// Mark whether to end the cycle 
		while (tmp != 1)
		{
			printf(" Please input your guess number ：", &a);
			scanf_s("%d", &a, 1);
			if (a == num)
			{
				printf(" That's right \n");
				tmp = 1;
				break;
			}
			else if (a < num)
			{
				printf(" Guess what \n");
			}
			else if (a > num)
			{
				printf(" Guess big \n");
			}
		}
		printf(" Please choose whether to continue the game ：Y(y)/N(n)\n");
		getchar();// Receive multiple input carriage returns 
		scanf_s("%c", &opt,1);
	}
	return 0;
}