用c++設計哲學家進餐問題的求解

#include<stdio.h>

#include<stdlib.h>

#include<pthread.h>

#include<iostream>

#include<unistd.h>

#include<semaphore.h>

#define N 5

#define LEFT i

#define RIGHT (i+1)%N

using namespace std;

class Semaphore{

   private:

      sem_t sem;

   public:

      Semaphore(int value=1){

          sem_init(&sem,0,value);

      }

      void P(){

          sem_wait(&sem);

      }

      void V(){

          sem_post(&sem);

      }

};

Semaphore mutex[N];

pthread_t thread[N];

int id[N];

int add=0;

void* solve(void*param){

    int i =*((int*)param);

    while(true){

       if(add>=30){

          cout<<"noodles is over"<<endl;

          break;

       }

       cout<<"philo"<<i<<"  thinking"<<endl;

       if(i%2==0){

          mutex[LEFT].P();

          mutex[RIGHT].P();

          cout<<"philo"<<i<<"  eatting"<<endl;

          add++;

          cout<<add<<endl;

          mutex[RIGHT].V();

          mutex[LEFT].V();

       }else{

          mutex[RIGHT].P();

          mutex[LEFT].P();

          cout<<"philo"<<i<<"  eatting"<<endl;

          add++;

          cout<<add<<endl;

          mutex[LEFT].V();

          mutex[RIGHT].V();

       }

       sleep(1);

    }

}

void thread_create(){

   int tmp;

   for(int i=0; i<N; i++){

      tmp=pthread_create(&thread[i],NULL,solve,&id[i]);

      if(tmp!=0){

          cout<<"thread"<<i<<"error"<<endl;

      }

   }

}

void thread_wait(){

    for(int i=0; i<N; i++){

       pthread_join(thread[i],NULL);

    }

}

int main(){

    for(int i=0; i<N; i++){

        id[i]=i;

    }

    thread_create();

    thread_wait();

    return 0;

}