c simple tcp server and clint

Quick example

/*
	C socket server example
*/

#include<stdio.h>
#include<string.h>	//strlen
#include<sys/socket.h>
#include<arpa/inet.h>	//inet_addr
#include<unistd.h>	//write

int main(int argc , char *argv[])
{
	int socket_desc , client_sock , c , read_size;
	struct sockaddr_in server , client;
	char client_message[2000];
	
	//Create socket
	socket_desc = socket(AF_INET , SOCK_STREAM , 0);
	if (socket_desc == -1)
	{
		printf("Could not create socket");
	}
	puts("Socket created");
	
	//Prepare the sockaddr_in structure
	server.sin_family = AF_INET;
	server.sin_addr.s_addr = INADDR_ANY;
	server.sin_port = htons( 8888 );
	
	//Bind
	if( bind(socket_desc,(struct sockaddr *)&server , sizeof(server)) < 0)
	{
		//print the error message
		perror("bind failed. Error");
		return 1;
	}
	puts("bind done");
	
	//Listen
	listen(socket_desc , 3);
	
	//Accept and incoming connection
	puts("Waiting for incoming connections...");
	c = sizeof(struct sockaddr_in);
	
	//accept connection from an incoming client
	client_sock = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c);
	if (client_sock < 0)
	{
		perror("accept failed");
		return 1;
	}
	puts("Connection accepted");
	
	//Receive a message from client
	while( (read_size = recv(client_sock , client_message , 2000 , 0)) > 0 )
	{
		//Send the message back to client
		write(client_sock , client_message , strlen(client_message));
	}
	
	if(read_size == 0)
	{
		puts("Client disconnected");
		fflush(stdout);
	}
	else if(read_size == -1)
	{
		perror("recv failed");
	}
	
	return 0;
}
The above code example will start a server on localhost (127.0.0.1) port 8888
Once it receives a connection, it will read some input from the client and reply back with the same message.
To test the server run the server and then connect from another terminal using the telnet command like this

$ telnet localhost 8888
Client

Now instead of using the telnet program as a client, why not write our own client program. Quite simple again

/*
	C ECHO client example using sockets
*/
#include<stdio.h>	//printf
#include<string.h>	//strlen
#include<sys/socket.h>	//socket
#include<arpa/inet.h>	//inet_addr

int main(int argc , char *argv[])
{
	int sock;
	struct sockaddr_in server;
	char message[1000] , server_reply[2000];
	
	//Create socket
	sock = socket(AF_INET , SOCK_STREAM , 0);
	if (sock == -1)
	{
		printf("Could not create socket");
	}
	puts("Socket created");
	
	server.sin_addr.s_addr = inet_addr("127.0.0.1");
	server.sin_family = AF_INET;
	server.sin_port = htons( 8888 );

	//Connect to remote server
	if (connect(sock , (struct sockaddr *)&server , sizeof(server)) < 0)
	{
		perror("connect failed. Error");
		return 1;
	}
	
	puts("Connected\n");
	
	//keep communicating with server
	while(1)
	{
		printf("Enter message : ");
		scanf("%s" , message);
		
		//Send some data
		if( send(sock , message , strlen(message) , 0) < 0)
		{
			puts("Send failed");
			return 1;
		}
		
		//Receive a reply from the server
		if( recv(sock , server_reply , 2000 , 0) < 0)
		{
			puts("recv failed");
			break;
		}
		
		puts("Server reply :");
		puts(server_reply);
	}
	
	close(sock);
	return 0;
}