C++ Program to Implement Stop and Wait Protocol

/* Stop and Wait Protocol: Sender sends one frame and wait for it's independent acknowledgement before sending
another one. 2 cases might occur:
1) Frame is lost so the acknowledgement doesn't come. Sender retransmits Frame.
2) Acknowledgement is lost. the sender retransmits frame. Seeing an already received frame, the receiver resends the acknowledgement and silently 
discards the duplicate packet. */

#include <iostream>
using namespace std;

struct Sender{
    int PacketNo;
    int Sent;
    int Acknowledged;
}S[6];

struct Receiver{
    int AcknowledgementNo;
    int Received;
    int AcknowledgementSent;
}R[6];

/* We are assuming the 4th data packet is lost and the acknowledgement of 6 data packet is also lost */
int i=0;

int main() {
    
    //Making the data packets at Sender side from 0 to 5
	for (i=0; i<6; i++){
	    S[i].Sent=0;
	    S[i].Acknowledged=0;
	    S[i].PacketNo=i;
	}
	
	//Making the data packets at Sender side from 1 to 6
	for (i=1; i<=6; i++){
	    R[i].AcknowledgementSent=0;
	    R[i].Received=0;
	    R[i].AcknowledgementNo=i;
	}
	
	int check4=0; int check6=0; //To study the cases of retransmission by manually causing data packet corruption
	
	//Sending and receiving the data packets
	for(i=0; i<6; i++){
	    cout<<"\n\n Next Transmission";
	    cout<<"\n Sending PacketNo "<<i<<" from Sender";
	    S[i].Sent=1;
	    cout<<"\n Propagation Delay";
	    if(i==4 && check4==0){
	        R[i].Received=0;
	        check4=1; i--;
	        cout<<"\n Data PacketNo "<<i<<" not received.";
	    }
	    else{
	        R[i].Received=1;
	        R[i].AcknowledgementSent=1;
	        cout<<"\n Sending AcknowledgementNo "<<i+1<<" to Sender";
	        cout<<"\n Propagation Delay";
	        if(i==5 && check6==0){
	            S[i].Acknowledged=0;
	            check6=1;i--;
	            cout<<"\n Acknowledgement for DataPacketNo"<< i <<" not received";
	        }
	        else{
	            S[i]. Acknowledged=1;
	            cout<<"\n Acknowledgement for PacketNo "<<i<<" Received";
	            
	        }
	        
	}}
	return 0;
}