生产者与消费者（单链表），一个单链表，有个表头和表尾，一个线程作为消费者每次从表头去一个元素，另一个线 程作为生产者每次从表尾加一个元素，不加锁如何实现?

single_read_write_queue.cc

#include <stdio.h>
#include <iostream>
#include <sstream>
#include <vector>
#include <set>
#include <list>
#include <map>
#include <thread>
#include <algorithm>
#include <stdio.h>
#include <math.h>
#include <chrono>
typedef long long lld;

using namespace std;

class SingleReadWriteQueue {
public:
    SingleReadWriteQueue() {
        tail = head = new Node(0);
    }

    void push(int v) {
        tail = tail->next = new Node(v);
    }

    bool pop(int &v) {
        if (head->next == NULL) {
            return false;
        }
        Node * tmp = head;
        head = head->next;
        v = head->val;
        delete tmp;
        return true;
    }
private:
    struct Node {
        Node(int v) {
            val = v;
            next = NULL;
        }
        int val;
        struct Node* next;
    };
    Node *head;
    Node *tail;
};

SingleReadWriteQueue g_q;

void push_queue() {
    long long i = 0; 
    while (1) {
        g_q.push(i);
        i = (i + 1) % 1000000;
        if (rand() % 1000 == 1) {
            this_thread::sleep_for(std::chrono::milliseconds(rand() % 519));
        }
    }
}

void pop_queue() {
    int v;
    long long i = 0;
    while (1) {
        int ret = g_q.pop(v);
        if (ret == false) {
            continue;
        }
        if (i != v) {
            cerr << "Error: " << i << " " << v << endl;
        }
        i = (i + 1) % 1000000;
        cout << i << endl;

        if (rand() % 2009 == 1) {
            this_thread::sleep_for(std::chrono::milliseconds(rand() % 719));
        }
    }
}

int main(int argc, char* argv[]) {
    thread push(push_queue);
    thread pop(pop_queue);

    push.join();
    pop.join();
    return 0;
}