如何为每个玩家生成不同的随机数？

Question

两位玩家都获得相同的随机数!我希望每个玩家得到一个不同的数字,因为他们掷骰子.这是代码:

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

int roll_a_dice(void);

int main(int argc, const char *argv[])
{   
    int flag;
    int answer1 = roll_a_dice();
    int answer2 = roll_a_dice();

    printf("Die 1 (rolled by player 1): %d\n", answer1);
    printf("Die 2 (rolled by player 2): %d\n", answer2);

    if (answer1>answer2) {
        printf("Player 1 is starting!\n");
        flag = 1;
    } else {
        printf("Player 2 is starting!\n");
        flag = 2;
    }

    printf("Goodbye!\n");

    return 0;        
}

int roll_a_dice(void)
{
    int r;

    srand(time(NULL));
    r = 1 + rand() % 6;

    return r;
}

球员们掷骰子.所以号码必须是1-6.我怎样才能解决这个问题？

Answer 1

srand ( time(NULL) );用于为伪随机数生成器播种.time()粒度为1秒,如果每次调用roll_a_dice()函数时播种PNRG ,对于在粒度周期内进行的所有调用,rand()最终将返回相同的随机数.

移动srand ( time(NULL) );出的roll_a_dice()函数,调用,只有在一次main().