生产者每次生产1个随机整数，放到缓冲区中；消费者每次从缓冲区中按生产顺序取出1个整数。每次缓冲区发生变化，打印放入/取出的数，以及缓冲当前大小。
情形1：初始为空，生产速率2/秒，消费速率1/秒
情形2：初始全满，生产速率1/秒，消费速率2/秒
情形3：初始半满，生产速率=消费速率
参考这个博客进行了一些改动
三个输入参数分别是当前的buffer中item的数量，生产者生产速率，消费者消费速率。
#include <mutex>
#include <condition_variable>
#include <windows.h>
#include <thread>
#include<iostream>using namespace std;static const int buffer_size = 128; // 缓存大小
static const int item_total = 300; //总共要生产 item_total个item
int produce_num = 1;
int consume_num = 1;// 缓存结构体, 使用循环队列当做缓存
struct Buffer
{int buffer[buffer_size];size_t read_position; // 当前读位置size_t write_position; // 当前写位置mutex mtx; // 读写互斥//条件变量condition_variable not_full;condition_variable not_empty;
} buffer_res;typedef struct Buffer Buffer;int get_write_position(Buffer *b)
{for (int i = 0; i < buffer_size; i++){if (0 == b->buffer[i]){return i;}}return buffer_size;
}int get_read_position(Buffer *b)
{for (int i = 0; i < buffer_size; i++){if (0 != b->buffer[i]){return i;}}return buffer_size;
}void porduce_item(Buffer *b)
{unique_lock<mutex> lock(b->mtx); //设置互斥锁while (1){b->write_position = get_write_position(b);if (b->write_position == buffer_size){//当前缓存已经满了cout << "buffer is full now, producer is wating....." << endl;(b->not_full).wait(lock); // 等待缓存非full}else{break;}}int item = rand() % buffer_size + 1;cout << "produce item: " << item << " in " << b->write_position << " ***" << endl;// 向缓存中添加item(b->buffer)[b->write_position] = item;(b->not_empty).notify_all();lock.unlock();
}int consume_item(Buffer *b)
{unique_lock<mutex> lock(b->mtx);while (1){b->read_position = get_read_position(b);if (b->read_position == buffer_size){// 当前buffer 为空cout << "buffer is empty , consumer is waiting....." << endl;(b->not_empty).wait(lock);}else{break;}}int item = (b->buffer)[b->read_position];(b->buffer)[b->read_position] = 0;cout << "consume item: " << item << " in " << b->read_position << endl;(b->not_full).notify_all();lock.unlock();return item;
}//生产者任务
void producer(int buf)
{for (int i = 1; i <= item_total - buf; i++){//生产item需要的时间Sleep(20 / produce_num);porduce_item(&buffer_res);}
}//消费者任务
void consumer()
{static int cnt = 0;while (1){//消费需要的时间Sleep(20 / consume_num);int item = consume_item(&buffer_res);if (++cnt == item_total)break;}
}//初始化 buffer, buf空满状态，p_num为produce_num, c_num为consume_num
void init_buffer(Buffer *b, const int buf)
{for (int i = 0; i < buf; i++){b->buffer[i] = rand() % buffer_size + 1;}for (int i = buf; i < buffer_size; i++){b->buffer[i] = 0;}
}int main(int argc, char **argv)
{int buf = 0;if (argc >= 4){buf = atoi(argv[1]);produce_num = atoi(argv[2]);consume_num = atoi(argv[3]);}else{cout << "Please enter the initial buffer items, ""produce_num ∈ {1,2} and consume_num ∈ {1,2}."<< endl;cin >> buf >> produce_num >> consume_num;}init_buffer(&buffer_res, buf);thread produce(producer, buf);thread consume(consumer);produce.join();consume.join();return 0;
}