add: correct version

Author: abhishekjiitr

Tutorial 2/client.cpp renamed to Tutorial 2/alt/client.cpp

@@ -0,0 +1,151 @@
+#include <iostream>
+#include <stdlib.h>
+#include <stdio.h>
+using namespace std;
+
+#define c1 "CLOSED"
+#define c2 "SYNSENT"
+#define c3 "CONNECTED"
+#define c4 "FINWAIT"
+#define invalid "INVALID"
+#define s1 "CLOSED"
+#define s2 "LISTENING"
+#define s3 "CONNECTED"
+#define s4 "CLOSEWAIT"
+#define SYN_MAX_RETRY 3
+#define FIN_MAX_RETRY 3
+
+class Server
+{
+	public:
+	string state;
+	Server()
+	{
+		state = s1;
+		serverState();
+		listen();
+	}
+	void listen()
+	{
+		int listen = -1;
+		while ( listen != 1 )
+		{
+			cout << "Press 1 to start Server listening:\n";
+			cin >> listen;
+		}
+		serverState();
+		state = s2;
+	}
+	void serverState()
+	{
+		cout << "Server State: " << state << endl;
+	}
+	int sendSyn()
+	{
+		return rand() % 2;
+	}
+	int sendFyn()
+	{
+		return rand() % 2;
+	}
+	void serverConnected()
+	{
+		state = s3;
+		serverState();
+	}
+	void serverClosed()
+	{
+		state = s4;
+		serverState();
+		cout << "CLOSE_WAIT_TIMEOUT\n";
+		state = s1;
+		listen();
+	}
+
+};
+
+int main()
+{
+	// freopen("input.in", "r", stdin);
+	Server svr;
+	string cstate = c1, input;
+	int result, in, tries;
+	while ( true )
+	{
+		cout << "Client State: " << cstate << endl;
+		
+		if ( cstate == c1 )
+		{
+			tries = 0;
+			cout << "Press 1 to send SYN\n";
+			cin >> in;
+			if ( in == 1 )
+			{
+				result = svr.sendSyn();
+				if ( result == 1 )
+					svr.serverConnected();
+				cstate = c3;
+			} 
+		}
+		else if ( cstate == c2 )
+		{
+			if ( result == 1 )
+			{
+				cstate = c3;
+				svr.serverConnected();
+			}
+			else
+			{
+				tries++;
+				if ( tries > SYN_MAX_RETRY  )
+					cstate = c1;
+				else
+				{
+					cout << "Press 1 to send SYN\n";
+					cin >> in;
+					if ( in == 1 )
+					{
+						result = svr.sendSyn();
+					}
+				}
+			}
+		}
+		else if ( cstate == c3 )
+		{
+			tries = 0;
+			cout << "Press 1 to send FIN\n";
+			cin >> in;
+			if ( in == 1 )
+			{
+				result = svr.sendFyn();
+				cstate = c4;
+			}
+		}	
+		else
+		{
+			if ( result == 1 )
+			{
+				cstate = c1;
+				svr.serverClosed();
+			}
+			else
+			{
+				tries++;
+				if ( tries > FIN_MAX_RETRY )
+					cstate = c1;
+				cout << "Press 1 to send FIN\n";
+				cin >> in;
+				if ( in == 1 )
+				{
+					result = svr.sendFyn();
+				}
+			}
+		}
+
+		if ( cstate == invalid )
+		{
+			cout << "Program Exiting\n";
+			break;
+		}
+	}
+}