philosopher.c

unix下实现5个哲学家之间的取食和思考的问题的一个实验

#include"apue.h"
#include"lock.h"
#include<unistd.h>

int main(int argc,char *argv[])
{
 int t,i;
 pid_t pid[6];
 if(argc>3||argc<1)
   err_quit(" usage: philosopher -t <time>");
 if(argc==3){
   if(strcmp(argv[1],"-t")!=0)
   err_sys("input error\n");
}
 if(argc==1){
  if(argv[1]=='\0')
   t=2;
 else{ 
   t=*(argv[2])-48;
   if(t<0 && t>9)
   err_sys(" time error \n");
 }
 }
 for(i=1;i<6;i++){
  if((pid[i]=fork())<0)
   err_sys("fork error");
  else if (pid[i]==0) continue;
//sleep(k);
  // k-=2;
// exit(7);
 // if(waitpid(pid[i],NULL,0)!=pid[i])
  // err_sys("wait error\n");
 }


  while(1){
  if(pid[1]==0){
  printf("the first philosopher is thinking \n");
  sleep(t);
  lock("2");
  lock("1");
  printf("the first phiosopher is eating \n");
  sleep(t);
  unlock("1");
  unlock("2");
  sleep(t);
  }
  if(pid[2]==0){
  sleep(t);
  printf("the second philosopher is thinking \n");
  lock("2");
  lock("3");
  printf("the second phiosopher is eating \n");
  sleep(t);
  unlock("2");
  unlock("3");
  sleep(t);
}
 if(pid[3]==0){
  sleep(t);
  printf("the third philosopher is thinking \n");
  lock("4");
  lock("3");
  printf("the third phiosopher is eating \n");
  sleep(t);
  unlock("4");
  unlock("3");
  sleep(t);
}
if(pid[4]==0){
  sleep(t);
  printf("the fourth philosopher is thinking \n");
  lock("4");
  lock("5");
  printf("the fourth phiosopher is eating \n");
  sleep(t);
  unlock("4");
  unlock("5");
  sleep(t);
}
if(pid[5]==0){
  sleep(t);
  printf("the fifth philosopher is thinking \n");
  lock("1");
  lock("5");
  printf("the fifth phiosopher is eating \n");
  sleep(t);
  unlock("1");
  unlock("5");
  sleep(t);
}//if
}//while
}