#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
// define function that deals with errors
void error(const char *msg)
{
	perror(msg); // print error msg
	exit(1); // exit the main() function
}

int main(int argc, char *argv[])
{
	int sockfd, newsockfd, portno; // defines ints
	socklen_t clilen; //size of address
	char buffer[256]; // buffer
	struct sockaddr_in serv_addr, cli_addr; // defines structures
	int n;

 	sockfd = socket(AF_INET, SOCK_STREAM, 0); // makes a socket
 	if (sockfd < 0)
 		error("ERROR opening socket"); // if socket creation failed

 	bzero((char *) &serv_addr, sizeof(serv_addr));

 	portno = atoi(argv[1]); // get port number

 	serv_addr.sin_family = AF_INET; // specify address family (IPv4)
 	serv_addr.sin_addr.s_addr = INADDR_ANY; // bind IP addresses
 	serv_addr.sin_port = htons(portno); // set port number

 	if (bind(sockfd, (struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0)
 		error("ERROR on binding"); // error while binding socket
 	listen(sockfd,5); // listen on created socket
 	clilen = sizeof(cli_addr);
 	newsockfd = accept(sockfd,(struct sockaddr *) &cli_addr,&clilen); // creates new socket for first incoming connection
 	if (newsockfd < 0)
 		error("ERROR on accept"); // error while creating socket
	while (1)
	{
		printf("Waiting for data\n");
		bzero(buffer,256);
	 	n = read(newsockfd,buffer,255); // read from connection socket
	 	if (n < 0) error("ERROR reading from socket"); // if error
	 	printf("Here is the message: %s\n",buffer); // show the message
	}
 	close(newsockfd); // close connection socket
 	close(sockfd); // close listening socket
 	return 0;
}