added code for sliding window, in testing phase

Codes/sliding-window.cpp

@@ -0,0 +1,64 @@
+#include <iostream>
+#include <vector>
+#include <queue>
+
+using namespace std;
+
+const int WINDOW_SIZE = 5; // size of the sliding window
+
+class SlidingWindow {
+private:
+    vector<int> sent_frames; // queue of sent frames
+    int next_frame_to_send; // index of the next frame to send
+    int next_frame_to_receive; // index of the next frame to receive
+
+public:
+    SlidingWindow() : next_frame_to_send(0), next_frame_to_receive(0) {}
+
+    // send a frame
+    void send_frame(int frame_number) {
+        if (sent_frames.size() < WINDOW_SIZE) {
+            sent_frames.push_back(frame_number);
+            next_frame_to_send++;
+            cout << "Sent frame " << frame_number << endl;
+        } else {
+            cout << "Window is full, cannot send frame " << frame_number << endl;
+        }
+    }
+
+    // receive a frame
+    void receive_frame(int frame_number) {
+        if (frame_number == next_frame_to_receive) {
+            next_frame_to_receive++;
+            cout << "Received frame " << frame_number << endl;
+        } else {
+            cout << "Received frame " << frame_number << ", but expected frame " << next_frame_to_receive << endl;
+        }
+
+        // remove acknowledged frames from the sent_frames queue
+        while (!sent_frames.empty() && sent_frames.front() <= next_frame_to_receive - 1) {
+            sent_frames.erase(sent_frames.begin());
+        }
+    }
+};
+
+int main() {
+    SlidingWindow window;
+
+    // send some frames
+    window.send_frame(0);
+    window.send_frame(1);
+    window.send_frame(2);
+    window.send_frame(3);
+    window.send_frame(4);
+    window.send_frame(5);
+
+    // receive some frames
+    window.receive_frame(0);
+    window.receive_frame(1);
+    window.receive_frame(2);
+    window.receive_frame(3);
+    window.receive_frame(4);
+
+    return 0;
+}