GOBackN.cpp

#include <iostream>
using namespace std;

int main()
{
    int count;
    cout << "Enter window size : ";
    int windowSize;
    cin >> windowSize;
    cout << "Enter total frames to be sent : ";
    int totalFrames;
    cin >> totalFrames;

    int senderFrames[totalFrames];
    for (int i = 0; i < totalFrames; i++)
        senderFrames[i] = i;

    for (int i = 0; i < totalFrames; i++)
        cout << senderFrames[i] << " | ";

    cout << endl;
    cout << "Do you want to start sending frames (0/1) : ";
    int choice;
    cin >> choice;
    cout << endl;

    if (choice == 1)
    {
        int ptrOnWindowLeftSender = 0;
        int ptrOnWindowLeftReceiver = 0;
        int totalSentFrames = 0;

        while (ptrOnWindowLeftSender < totalFrames)
        {
            count = 0;
            cout << "At Sender End:" << endl;
            for (int i = ptrOnWindowLeftSender;
                 (i < totalFrames && count < windowSize); i++)
            {
                cout << "Sent frame[" << (i + 1) << "]" << endl;
                ptrOnWindowLeftSender++;
                totalSentFrames++;
                count++;
            }
            cout << endl;

            // Receiver side
            cout << "At Receiver end: " << endl;
            int j = 0;
            count = 0;
            for (int i = ptrOnWindowLeftReceiver;
                 (i < totalFrames && count < windowSize); i++)
            {
                char yN;
                cout << "Did you receive frame[" << (i + 1) << "] (y/n) : ";
                cin >> yN;
                if (yN == 'n')
                {
                    cout << "Frames will be sent again from frame no. " << (i + 1)
                         << endl;
                    cout << endl;
                    ptrOnWindowLeftSender = i;
                    break;
                }
                else
                {
                    j++;
                    ptrOnWindowLeftReceiver++;
                }
                count++;
            }

            if (j == windowSize)
            {
                cout << "All Frames from this window sent without errors. Sending next "
                        "frames..."
                     << endl;
                cout << endl;
            }
        }

        cout << endl;
        cout << "All frames are sent." << endl;
        cout << "Total no. of frames sent including retransmission is "
             << totalSentFrames << endl;
    }

    return 0;
}