请用C++代码编写完成以下要求，需要有注释，里面的数据用随机函数自己生成：二、Readers-Writer Problem Implmentation 1、 A data set is shared among several concurrent processes: Readers – only read the data set; they do not perform any updates. Writers – can both read and write. 2、 Problem – allow multiple readers (at most 8) to read at the same time. Only one single writer can access the shared data at the same time.三、Program for Least Recently used Algorithm 1、 Create a page access sequence (page number range 0-18) using a random function. The sequence length is 54 and assume that the number of main memory frames allocated to the thread is 6, that is, M = 6. 2、 Implement the LRU algorithm for page replacement on the above access sequence. 3、 Output the page replacement sequence and the page fault rate.

以下是C++代码实现：

// Readers and Writers Problem Implementation

#include <iostream>
#include <thread>
#include <mutex>
#include <chrono>
#include <random>

using namespace std;

mutex mtx;
int data_set = 0;
int reader_count = 0;

void reader(int id) {
// Acquire lock before accessing shared data
unique_lock<mutex> lock(mtx);

// Increment reader count
reader_count++;

// Release lock to allow other readers to read
lock.unlock();

// Read shared data
cout << "Reader " << id << " read data: " << data_set << endl;

// Acquire lock before decrementing reader count
lock.lock();

// Decrement reader count
reader_count--;

// Notify waiting writers if no readers remain
if (reader_count == 0) {
lock.unlock();
}
}

void writer(int id) {
// Acquire lock before accessing shared data
unique_lock<mutex> lock(mtx);

// Wait for all readers to finish reading
while (reader_count > 0) {
lock.unlock();
this_thread::sleep_for(chrono::milliseconds(10));
lock.lock();
}

// Write to shared data
data_set++;
cout << "Writer " << id << " wrote data: " << data_set << endl;

// Release lock
lock.unlock();
}

int main() {
// Create 8 readers and 1 writer
thread readers[8];
thread writer(writer, 1);

// Start readers
for (int i = 0; i < 8; i++) {
readers[i] = thread(reader, i + 1);
}

// Join threads
for (int i = 0; i < 8; i++) {
readers[i].join();
}
writer.join();

return 0;
}

// Program for Least Recently used Algorithm

#include <iostream>
#include <list>
#include <random>

using namespace std;

int main() {
// Generate page access sequence using random function
random_device rd;
mt19937 gen(rd());
uniform_int_distribution<> dis(0, 18);
list<int> page_access_sequence;
for (int i = 0; i < 54; i++) {
page_access_sequence.push_back(dis(gen));
}

// LRU algorithm for page replacement
int M = 6; // Number of main memory frames
list<int> main_memory;
int page_faults = 0;
for (auto it = page_access_sequence.begin(); it != page_access_sequence.end(); ++it) {
// Check if page is already in main memory
auto pos = find(main_memory.begin(), main_memory.end(), *it);
if (pos != main_memory.end()) {
// Page hit, move page to front of list
main_memory.erase(pos);
main_memory.push_front(*it);
} else {
// Page fault, replace least recently used page
page_faults++;
if (main_memory.size() == M) {
main_memory.pop_back();
}
main_memory.push_front(*it);
}
}

// Output page replacement sequence and page fault rate
cout << "Page replacement sequence: ";
for (auto it = main_memory.begin(); it != main_memory.end(); ++it) {
cout << *it << " ";
}
cout << endl;
cout << "Page fault rate: " << (double)page_faults / (double)54 << endl;

return 0;
}