C++ server client chatting

Question

1.12/5 (4 votes)

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client server messaging same pcs but doesn`t work seperate computers.

What I have tried:

Client.cpp

#include<iostream>
#include<string.h>
#include
#include
#include
#include
#include<stdlib.h>
#include<unistd.h>
#include<netdb.h>
using namespace std;

#define IP "192.168.56.1"
int main(){
     int client,server;
    int portNum=1500;
    bool isExit=false;
    int bufsize=1024;
    char buffer[bufsize];

   // char *ip= "192.168.1.101";
     struct sockaddr_in server_addr;
     client=socket(AF_INET,SOCK_STREAM,0);
     
     if(client<0){
        cout<< "Error createing socket." <<endl;
        exit(1);
        
        }
        
         cout<< "Client Socket created." <<endl;
        server_addr.sin_family=AF_INET;
        
     server_addr.sin_addr.s_addr = inet_addr(IP);
        server_addr.sin_port=htons(portNum);
        if (connect(client,(struct sockaddr *)&server_addr, sizeof(server_addr)) == 0)
        cout << "=> Connection to the server " << inet_ntoa(server_addr.sin_addr) << " with port number: " << portNum << endl; 
             recv(client,buffer,bufsize,0);
             cout<< "Connection confirmed." <<endl;
            cout<< "Enter # to end the connection." <<endl;
            
            do{
                 cout<< "Client:" << " " ;
                 do{
                     cin >> buffer;
                send(client,buffer,bufsize,0);
                 if(*buffer=='#'){
                                send(client,buffer,bufsize,0);
                                *buffer='*';
                                isExit=true;
                                }
                 }while(*buffer != 42);
                  cout<< "Server:  " << " " ;
                   do{
                                 recv(client,buffer,bufsize,0);
                                   cout<< buffer << " ";
                                    if(*buffer=='#'){
                                        *buffer='*';
                                        isExit=true; 
                                        
                                        }
                   }while(*buffer != 42);
                   cout << endl;
            }while(!isExit);
              cout<< "Connection terminated." <<endl; 
                close(client);
                return 0;
    }

Server.cpp

#include<iostream>
#include<string.h>
#include
#include
#include
#include<stdlib.h>
#include<unistd.h>
#include

#define IP "127.0.0.1"

using namespace std;
int main(){
    
    int client,server;
    int portNum=1500;
    bool isExit=false;
    int bufsize=1024;
    char buffer[bufsize];
    struct sockaddr_in server_addr;
    socklen_t size;
    client=socket(AF_INET,SOCK_STREAM,0);
    if(client<0){
        cout<< "Error establishing connection." <<endl;
        exit(1);
        
        }
        cout<< "Server Socket connection created." <<endl;
        server_addr.sin_family=AF_INET;
        server_addr.sin_addr.s_addr = htons(INADDR_ANY);
        server_addr.sin_port= htons(portNum);
        
        //binding socket
        
        if(bind(client, (struct sockaddr*)&server_addr,sizeof(server_addr))<0){
             cout<< "Error binding socket." <<endl;
             exit(1);
            }
            size=sizeof(server_addr);
            cout<< "Looking for clients" <<endl;
        //listening socket
        
            listen(client,1);
        //accept client
        
            server = accept(client,(struct sockaddr*)&server_addr,&size);
            if(server<0){
                cout<< "Error on accepting." <<endl;
             exit(1);
                
                }
                
                while(server>0){
                    
                    strcpy(buffer,"Server connected..\n");
                    send(server,buffer,bufsize,0);
                    cout<< "Connected with client." <<endl;
                    cout<< "Enter # to end the connection." <<endl;
                    cout<< "Client: " << " " ;
                    
                     do{
                        recv(server,buffer,bufsize,0);
                        cout<< buffer << " ";
                        if(*buffer=='#'){
                            *buffer='*';
                            isExit=true;
                            }
                        }while(*buffer!= '*');
                          
                       
                        do{
                            cout << "\nServer:" <<  " ";
                            do{
                                cin>>buffer;
                                send(server,buffer,bufsize,0);
                                 if(*buffer=='#'){
                                send(server,buffer,bufsize,0);
                                *buffer='*';
                                isExit=true;
                                }
                            }while(*buffer != '*');
                            
                             cout<< "Client:  " << " " ;
                             do{
                                 recv(server,buffer,bufsize,0);
                                   cout<< buffer << " ";
                                    if(*buffer=='#'){
                                        *buffer='*';
                                        isExit=true; 
                                        
                                        }
                                 }while(*buffer != '*');
                            
                        }while(!isExit);
                 cout<< "Connection terminated." <<endl; 
                 isExit=false;
                 exit(1) ;
             }
close(client);
return 0;     
                            
    }

Posted 3-Mar-16 3:46am

Member 11351616

Updated 27-Oct-22 20:45pm

Jochen Arndt

v5

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Comments

Jochen Arndt 3-Mar-16 9:52am

Has the server the IP 192.168.56.1 and is the client in the same subnet (has an IP 192.168.56.x)?

Member 11351616 4-Mar-16 4:16am

The client and server has to be same wifi but different computers.So my client ip and server ip different.How can i connect server from client?

Jochen Arndt 4-Mar-16 4:39am

You did not really answered my question.

However, when they are in the same subnet ensure that:
- The client uses the correct server IP (when using WiFi use the IP address of the WiFi interface)
- There is no firewall blocking your packets (check on the server and the WiFi router)

Member 11351616 4-Mar-16 5:56am

okey i got it.I will check it.Also server_addr.sin_addr.s_addr = inet_addr(IP); when i use the this code on the client.cpp , it does not work correctly. Can u check my code ? I am new C++, its my first codes.

Jochen Arndt 4-Mar-16 6:03am

What do you mean by "not work correctly"?

Member 11351616 4-Mar-16 6:11am

when i use the ip adress(different from localhost) and run the code,client doensn`t connect server.Just I am getting client socket created message on the terminal.Normally it has to be connection comfirmed and i can send message to server.

Jochen Arndt 4-Mar-16 6:38am

It is not the quoted line that fails.
What fails is the call to connect().

You are already checking the return value. So add an else condition to print out that the connection failed.

To know the reason, check the global variable errno (include errno.h on top of your client file) and print out the value. An error message string can be retrieved by passing the error code to strerror:

else
{
int err = errno;
cout << "Connection failed with code " << err << ": " << strerror(err) << endl;
}

The print out should help you (and us) to narrow down what happens.

Member 11351616 4-Mar-16 7:33am

i get it connection failed with code 111:connection refused.

Jochen Arndt 4-Mar-16 7:47am

That means no-one listening on the remote address but may be also sourced by a firewall. Is the server still runnning?

To check the network connection try pinging the server from the client. In a shell on the client enter (press Ctrl+C on Linux to stop)
'ping 192.168.56.1'

If this fails the problem is network related and not with your program.

Arthur V. Ratz 21-Mar-16 2:15am

5.

[no name] 3-Mar-16 10:37am

There's some code missing. Are you bind()-ing the server socket?

Member 11351616 4-Mar-16 4:10am

yes i bind the server socket.Here i updated my code.This code is working in localhost.

Arthur V. Ratz 21-Mar-16 2:16am

5.

Richard MacCutchan 4-Mar-16 5:49am

Are you sure the server's local IP address is 192.168.56.1? When PCs connect via wifi their IP addresses sometimes change.

Member 11351616 4-Mar-16 5:59am

yes i am sure the ip address.

Richard MacCutchan 4-Mar-16 6:07am

Well there is nothing we can guess from the above. The only thing to do is to get with your debugger to trace exactly what is happening when you run your code. Basic socket connections between PCs is not that complicated and as long as the addresses and port numbers are correct, it should just work.

Jochen Arndt 4-Mar-16 7:57am

Are you really sure?
The .1 address is usually occupied by the DHCP server itself (e.g. the router) and not assigned to clients.

To know the address execute 'ipconfig' at a Windows command prompt or 'ifconfig' at a Linux shell prompt and locate the IP address of the WiFi interface.

Arthur V. Ratz 21-Mar-16 2:16am

5.

Arthur V. Ratz 20-Mar-16 11:18am

If you're writing a program that performs client-server chatting using plain text, you would better implement a service which will receive messages from client applications.

1 solution

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This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

leon de boer · Answer 1 · 2016-04-24T15:33:00

Solution 1

The answer to why it wont work on seperate PC's is simple and nothing to do with your code.

It's called a FIREWALL you are using port 1500 you will need to open that port on the firewalls on both PC's.

Assuming you are on windows, (search appropriate if on linux):
Open a port in Windows Firewall - Windows Help[^]

Posted 24-Apr-16 15:33pm

leon de boer

Updated 24-Apr-16 17:45pm

v2

Comments

[no name] 22-Feb-22 8:52am

Hi, Leon de boer Thanx for Solution 1. It was the same i ussue lately i have, i worked on firewall settings as in solution 1, it helps for LAN. What about both computers connected internet through different internet service providers? Frankly i did test it but it did not work!

C++ server client chatting

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