Implementation of server – client using TCP socket programming

```` Server Side

#include <stdio.h> 
#include <netdb.h> 
#include <netinet/in.h> 
#include <stdlib.h> 
#include <string.h> 
#include <sys/socket.h> 
#include <sys/types.h> 
#include <unistd.h> // read(), write(), close()
#define MAX 80 
#define PORT 8080 
#define SA struct sockaddr 

// Function designed for chat between client and server. 
void func(int connfd) 
{ 
	char buff[MAX]; 
	int n; 
	// infinite loop for chat 
	for (;;) { 
		bzero(buff, MAX); 

		// read the message from client and copy it in buffer 
		read(connfd, buff, sizeof(buff)); 
		// print buffer which contains the client contents 
		printf("From client: %s\t To client : ", buff); 
		bzero(buff, MAX); 
		n = 0; 
		// copy server message in the buffer 
		while ((buff[n++] = getchar()) != '\n') 
			; 

		// and send that buffer to client 
		write(connfd, buff, sizeof(buff)); 

		// if msg contains "Exit" then server exit and chat ended. 
		if (strncmp("exit", buff, 4) == 0) { 
			printf("Server Exit...\n"); 
			break; 
		} 
	} 
} 

// Driver function 
int main() 
{ 
	int sockfd, connfd, len; 
	struct sockaddr_in servaddr, cli; 

	// socket create and verification 
	sockfd = socket(AF_INET, SOCK_STREAM, 0); 
	if (sockfd == -1) { 
		printf("socket creation failed...\n"); 
		exit(0); 
	} 
	else
		printf("Socket successfully created..\n"); 
	bzero(&servaddr, sizeof(servaddr)); 

	// assign IP, PORT 
	servaddr.sin_family = AF_INET; 
	servaddr.sin_addr.s_addr = htonl(INADDR_ANY); 
	servaddr.sin_port = htons(PORT); 

	// Binding newly created socket to given IP and verification 
	if ((bind(sockfd, (SA*)&servaddr, sizeof(servaddr))) != 0) { 
		printf("socket bind failed...\n"); 
		exit(0); 
	} 
	else
		printf("Socket successfully binded..\n"); 

	// Now server is ready to listen and verification 
	if ((listen(sockfd, 5)) != 0) { 
		printf("Listen failed...\n"); 
		exit(0); 
	} 
	else
		printf("Server listening..\n"); 
	len = sizeof(cli); 

	// Accept the data packet from client and verification 
	connfd = accept(sockfd, (SA*)&cli, &len); 
	if (connfd < 0) { 
		printf("server accept failed...\n"); 
		exit(0); 
	} 
	else
		printf("server accept the client...\n"); 

	// Function for chatting between client and server 
	func(connfd); 

	// After chatting close the socket 
	close(sockfd); 
}


````` Client side

#include <arpa/inet.h> // inet_addr()
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h> // bzero()
#include <sys/socket.h>
#include <unistd.h> // read(), write(), close()
#define MAX 80
#define PORT 8080
#define SA struct sockaddr
void func(int sockfd)
{
	char buff[MAX];
	int n;
	for (;;) {
		bzero(buff, sizeof(buff));
		printf("Enter the string : ");
		n = 0;
		while ((buff[n++] = getchar()) != '\n')
			;
		write(sockfd, buff, sizeof(buff));
		bzero(buff, sizeof(buff));
		read(sockfd, buff, sizeof(buff));
		printf("From Server : %s", buff);
		if ((strncmp(buff, "exit", 4)) == 0) {
			printf("Client Exit...\n");
			break;
		}
	}
}

int main()
{
	int sockfd, connfd;
	struct sockaddr_in servaddr, cli;

	// socket create and verification
	sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if (sockfd == -1) {
		printf("socket creation failed...\n");
		exit(0);
	}
	else
		printf("Socket successfully created..\n");
	bzero(&servaddr, sizeof(servaddr));

	// assign IP, PORT
	servaddr.sin_family = AF_INET;
	servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");
	servaddr.sin_port = htons(PORT);

	// connect the client socket to server socket
	if (connect(sockfd, (SA*)&servaddr, sizeof(servaddr))
		!= 0) {
		printf("connection with the server failed...\n");
		exit(0);
	}
	else
		printf("connected to the server..\n");

	// function for chat
	func(sockfd);

	// close the socket
	close(sockfd);
}