add mutex

03.Advanced/Mutex.cpp

+#include <iostream>
+#include <mutex>
+#include <queue>
+#include <cstdlib>
+#include <unistd.h>
+#include <thread>
+
+using namespace std;
+
+// 打印日志
+void printMsg(string msg) {
+
+    cout << msg + "\n";
+
+}
+
+// 线程安全类，该类会被用来初始化一次，然后通过引用传递，给多个线程轮流操作
+class ThreadSafeQueue {
+
+    private:
+
+        // int队列
+        queue<int> rawQueue;
+        // 排他锁
+        mutex m;
+    
+    public:
+
+        // 打印包含线程名的日志
+        void printLocalMsg(string msg, string name) {
+
+            printMsg("[" + name + "] " + msg);
+
+        }
+
+        // 从队列取值
+        void retrieveAndDelete(int sleepSec, string name) {
+
+            int frontValue = 0;
+
+            // 取值之前，加上排他锁，防止其他线程并行操作
+            m.lock();
+            printLocalMsg("Lock pop", name);
+            if (!rawQueue.empty()) {
+
+                frontValue = rawQueue.front();
+                printLocalMsg("Retrieved front value " + to_string(frontValue), name);
+                rawQueue.pop();
+                printLocalMsg("Front value popped", name);
+
+            }
+            // 取值完成后，释放锁，使其他线程可以继续操作
+            printLocalMsg("Unlock pop", name);
+            m.unlock();
+
+        }
+
+        // 向队列里存放值
+        void push(int val, int sleepSec, string name) {
+
+            // 存放值之前，加上排他锁，防止其他线程并行操作
+            m.lock();
+            printLocalMsg("Lock push", name);
+            printLocalMsg("Sleep for " + to_string(sleepSec), name);
+            sleep(sleepSec);
+            printLocalMsg("Push " + to_string(val), name);
+            rawQueue.push(val);
+            // 存放值完成后，释放锁，使其他线程可以继续操作
+            printLocalMsg("Unlock push", name);
+            m.unlock();
+
+        }
+
+};
+
+// 定义线程操作
+void run(int tid, string name, ThreadSafeQueue & tsq) {
+
+    // 取随机数 1-5
+    int random = rand() % 5 + 1;
+
+    string msg;
+    msg = "Start thread " + to_string(tid) + ":" + name
+            + " with random " + to_string(random);
+    tsq.printLocalMsg(msg, name);
+
+    // 从线程取值
+    tsq.retrieveAndDelete(random, name);
+    // 向线程存放值
+    tsq.push(random, random, name);
+
+}
+
+int main() {
+
+    // Get random int from 1-5
+    int random = rand() % 5 + 1;
+
+    ThreadSafeQueue tsq;
+    tsq.push(0, 0, "main");
+
+    thread t0(run, 1, "Red", ref(tsq));
+    thread t1(run, 2, "Green", ref(tsq));
+    thread t2(run, 3, "Blue", ref(tsq));
+    thread t3(run, 4, "Yellow", ref(tsq));
+
+    t0.join();
+    t1.join();
+    t2.join();
+    t3.join();
+
+    tsq.retrieveAndDelete(0, "main");
+
+}
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