Re: [問題] 亂數問題

[jlovet ( Q我~)]

如果不用glibc的rand...
那...就把他的公式抄過來就好...
http://www.cs.ccu.edu.tw/~ksc91u/rand/rand_pthread.c

#include <pthread.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
void * msrand(void * data);
int my_rand_r (unsigned int *seed);

struct p{
        int * data;
        int id;
};

int main(){
        pthread_t pt[5];
        struct p pp[5];
        int d[5]={7919,22307,48611,104729,287117};
        for(int i=0;i<5;i++){
                pp[i].data=&d[0];
                pp[i].id=i;
                pthread_create(&pt[i],NULL,msrand,&pp[i]);
        }
        for(int i=0;i<5;i++){
                pthread_join(pt[i],NULL);
        }
        printf("%d %d %d %d %d\n",d[0],d[1],d[2],d[3],d[4]);

}
static unsigned int seed;

int my_srand(unsigned int s){
        seed=s;
}

unsigned int my_rand(){
//      seed=my_rand_r(&seed);
//      return seed;
        return my_rand_r(&seed);
}

int
my_rand_r (unsigned int *seed)
{
  unsigned int next = *seed;
  int result;

  next *= 1103515245;
  next += 12345;
  result = (unsigned int) (next / 65536) % 2048;

  next *= 1103515245;
  next += 12345;
  result <<= 10;
  result ^= (unsigned int) (next / 65536) % 1024;

  next *= 1103515245;
  next += 12345;
  result <<= 10;
  result ^= (unsigned int) (next / 65536) % 1024;

  *seed = next;

  return result;
}


void * msrand(void * data){
        struct p * pp = (struct p *) data;
        int * ptr=pp->data;
        int self=pp->id;
        my_srand(ptr[(self+1)%5]);
        for(int i=0;i<100;i++){
                ptr[self]^=my_rand();
                ptr[self]<<13;
                usleep(1);
                sched_yield();
        }
}



其實也可以不用pthread...
用alarm..來模擬thread的效果..

--
※ 發信站: 批踢踢實業坊(ptt.cc) 
◆ From: 140.123.102.254
→ jlovet:http://tinyurl.com/336xpz ualarm版本
推 GiPaPa:感謝 我再研究一下<(_ _)>