s_and_r.c

c primer plus 第五版 的源代码

/* s_and_r.c -- file for rand1() and srand1()    */
/*                uses ANSI C portable algorithm */
static unsigned long int next = 1;  /* the seed  */

int rand1(void)
{
/* magic formula to generate pseudorandom number */
    next = next * 1103515245 + 12345;
    return (unsigned int) (next/65536) % 32768;
}

void srand1(unsigned int seed)
{
    next = seed;
}