C 多线程题目

题目：

有四个线程1、2、3、4。线程1的功能就是输出1，线程2的功能就是输出2，以此类推.........现在有四个文件ABCD。初始都为空。现要让四个文件呈如下格式：

A：1 2 3 4 1 2....

B：2 3 4 1 2 3....

C：3 4 1 2 3 4....

D：4 1 2 3 4 1....

请设计程序。

程序：

/*****************************************************
copyright (C), 2014-2015, Lighting Studio. Co.,     Ltd. 
File name：
Author：Jerey_Jobs    Version:0.1    Date: 
Description：
Funcion List: 
*****************************************************/


#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <errno.h>


FILE *f1;
FILE *f2;
FILE *f3;
FILE *f4;


pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t condA_B = PTHREAD_COND_INITIALIZER;
pthread_cond_t condB_C = PTHREAD_COND_INITIALIZER;
pthread_cond_t condC_D = PTHREAD_COND_INITIALIZER;
pthread_cond_t condD_A = PTHREAD_COND_INITIALIZER;


int flaga,flagb,flagc,flagd;


void *th_fun_a(void *arg)
{
int i = 0;


while(i < 10)
{
pthread_mutex_lock(&mutex);
flaga = 1;
pthread_cond_wait(&condD_A,&mutex);
flaga = 0;


f1 = fopen("A.txt","a+");
fseek(f1,0,SEEK_END);
fputc('1',f1);
fclose(f1);

f2 = fopen("B.txt","a+");
fseek(f2,0,SEEK_END);
fputc('2',f2);
fclose(f2);


f3 = fopen("C.txt","a+");
fseek(f3,0,SEEK_END);
fputc('3',f3);
fclose(f3);


f4 = fopen("D.txt","a+");
fseek(f4,0,SEEK_END);
fputc('4',f4);
fclose(f4);


while(!flagb)
{
pthread_mutex_unlock(&mutex);
usleep(50);
pthread_mutex_lock(&mutex);
}


pthread_cond_broadcast(&condA_B);
pthread_mutex_unlock(&mutex);

i++;
usleep(50);


}
flaga = 1;
}


void *th_fun_b(void *arg)
{
int i = 0;


while(i < 10)
{
pthread_mutex_lock(&mutex);
flagb = 1;
pthread_cond_wait(&condA_B,&mutex);
flagb = 0;


f1 = fopen("A.txt","a+");
fseek(f1,0,SEEK_END);
fputc('2',f1);
fclose(f1);

f2 = fopen("B.txt","a+");
fseek(f2,0,SEEK_END);
fputc('3',f2);
fclose(f2);


f3 = fopen("C.txt","a+");
fseek(f3,0,SEEK_END);
fputc('4',f3);
fclose(f3);


f4 = fopen("D.txt","a+");
fseek(f4,0,SEEK_END);
fputc('1',f4);
fclose(f4);


while(!flagc)
{
pthread_mutex_unlock(&mutex);
usleep(50);
pthread_mutex_lock(&mutex);
}


pthread_cond_broadcast(&condB_C);
pthread_mutex_unlock(&mutex);

i++;
usleep(50);


}
}


void *th_fun_c(void *arg)
{
int i = 0;


while(i < 10)
{
pthread_mutex_lock(&mutex);
flagc = 1;
pthread_cond_wait(&condB_C,&mutex);
flagc = 0;


f1 = fopen("A.txt","a+");
fseek(f1,0,SEEK_END);
fputc('3',f1);
fclose(f1);

f2 = fopen("B.txt","a+");
fseek(f2,0,SEEK_END);
fputc('4',f2);
fclose(f2);


f3 = fopen("C.txt","a+");
fseek(f3,0,SEEK_END);
fputc('1',f3);
fclose(f3);


f4 = fopen("D.txt","a+");
fseek(f4,0,SEEK_END);
fputc('2',f4);
fclose(f4);


while(!flagd)
{
pthread_mutex_unlock(&mutex);
usleep(50);
pthread_mutex_lock(&mutex);
}


pthread_cond_broadcast(&condC_D);
pthread_mutex_unlock(&mutex);

i++;
usleep(50);


}
}


void *th_fun_d(void *arg)
{
int i = 0;


while(i < 10)
{
pthread_mutex_lock(&mutex);
flagd = 1;
pthread_cond_wait(&condC_D,&mutex);
flagd = 0;


f1 = fopen("A.txt","a+");
fseek(f1,0,SEEK_END);
fputc('4',f1);
fclose(f1);

f2 = fopen("B.txt","a+");
fseek(f2,0,SEEK_END);
fputc('1',f2);
fclose(f2);


f3 = fopen("C.txt","a+");
fseek(f3,0,SEEK_END);
fputc('2',f3);
fclose(f3);


f4 = fopen("D.txt","a+");
fseek(f4,0,SEEK_END);
fputc('3',f4);
fclose(f4);


while(!flaga)
{
pthread_mutex_unlock(&mutex);
usleep(50);
pthread_mutex_lock(&mutex);
}


pthread_cond_broadcast(&condD_A);
pthread_mutex_unlock(&mutex);

i++;
usleep(50);


}
}


int main()
{
pthread_t th[4];


void *(*th_funs[])(void *) = 
{
th_fun_a,
th_fun_b,
th_fun_c,
th_fun_d,
};


int i;


for(i = 0; i < 4; i++)
{
if(pthread_create(th+i,NULL,th_funs[i],(void *)i) < 0)
{
fprintf(stderr,"creat:%s\n",strerror(errno));
exit(-1);
}
}


pthread_mutex_lock(&mutex);
while(!flagd)
{
pthread_mutex_unlock(&mutex);
usleep(50);
pthread_mutex_lock(&mutex);
}
printf("hi\n");
pthread_cond_broadcast(&condD_A);
pthread_mutex_unlock(&mutex);


for(i = 0; i < 4; i++)
{
pthread_join(th[i],NULL);
printf("process %d finished!\n",i);
}


    return 0;
}



题目