simulating received frames and added user inputs

Codes/CRC.cpp

@@ -43,6 +43,35 @@ string encoder(string data, string key) {
     return data + crc;
 }
 
+string performDivision(string data, string key) {
+    int keyLen = key.length();
+
+    // Initialize with the data to be divided
+    string temp = data.substr(0, keyLen);
+
+    // Perform XOR operations on each segment
+    for (int i = keyLen; i < data.length(); i++) {
+        if (temp[0] == '1') {  // Only perform XOR if the leading bit is 1
+            temp = XOR(temp, key);
+        }
+        temp = temp.substr(1) + data[i];  // Shift left and add the next bit
+    }
+
+    // Perform the final XOR operation
+    if (temp[0] == '1') {
+        temp = XOR(temp, key);
+    }
+
+    // Extract the remainder (last keyLen-1 bits)
+    return temp.substr(temp.length() - (keyLen - 1));
+}
+
+// Function to check the correctness of received data
+bool checkData(string data, string key) {
+    string remainder = performDivision(data, key);
+    return (remainder.find('1') == string::npos); // No '1' means remainder is all zeros
+}
+
 int main() {
     string data, key;
 
@@ -51,13 +80,23 @@ int main() {
     cout << "Enter primary key:\t";
     getline(cin, key);
 
+    cout<<endl<<"Original data:\t"<<data;
+    cout<<endl<<"Key:\t"<<key;
     string messageToSend = encoder(data, key);
-    cout<<endl<<"--------------------"<<endl;
+    cout<<endl<<"----------------------------------------"<<endl;
     cout<<"Message to be sent:\t"<<messageToSend;
-    cout<<endl<<"--------------------"<<endl;
+    cout<<endl<<"----------------------------------------"<<endl;
+
+    string receivedData;
+    cout<<endl<<"HINT: Received data should be the same as message to be sent.";
+    cout<<endl<<"Enter received data:\t";
+    getline(cin, receivedData);
+
+    if (receivedData == messageToSend) {
+        cout<<"The received data is correct."<<endl;
+    } else {
+        cout<<"The received data appears to be tampered."<<endl;
+    }
 
     return 0;
 }
-
-// TODO:
-// - Check if input data is actually binary

Codes/sliding-window.cpp

@@ -0,0 +1,79 @@
+#include <iostream>
+#include <vector>
+#include <queue>
+
+using namespace std;
+
+class SlidingWindow {
+private:
+    int window_size;
+    int total_frames;
+    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(int window_size, int total_frames) {
+    this->window_size = window_size;
+    this->total_frames = total_frames;
+    this->next_frame_to_send = 0;
+    this->next_frame_to_receive = 0;
+  }
+
+    // send a frame
+    void send_frame() {
+        if (sent_frames.size() < window_size && next_frame_to_send < total_frames) {
+            sent_frames.push_back(next_frame_to_send);
+            next_frame_to_send++;
+            cout << "Sent frame " << sent_frames.back() << endl;
+        } else {
+            cout << "Window is full. Waiting before sending next frames." << 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());
+        }
+    }
+
+    bool all_frames_sent() {
+        return next_frame_to_send == total_frames;
+    }
+
+    bool all_frames_received() {
+        return next_frame_to_receive == total_frames;
+    }
+};
+
+int main() {
+    int window_size, total_frames;
+    cout << "Enter the window size:\t";
+    cin >> window_size;
+    cout << "Enter the total number of frames:\t";
+    cin >> total_frames;
+
+    SlidingWindow window(window_size, total_frames);
+
+    while (!window.all_frames_sent() || !window.all_frames_received()) {
+        window.send_frame();
+
+        // simulate receiving frames
+        for (int i = 0; i < rand() % 3; i++) {
+            int frame_number = rand() % total_frames;
+            window.receive_frame(frame_number);
+        }
+    }
+    cout << "All frames sent and received successfully!" << endl;
+
+    return 0;
+}