1_server.c

// Server side C/C++ program to demonstrate Socket programming
#include <stdio.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <string.h>

#define PORT 8081

char *reverse(char* S)
{
	int n=strlen(S);
	for(int i=0;i<n/2;i++)
	{
		char c=S[i];
		S[i]=S[n-i-1];
		S[n-i-1]=c;
	}
	return S;
}


int main(int argc, char const *argv[])
{
	int server_fd, new_socket, valread;
	struct sockaddr_in address;
	int opt = 1;
	int addrlen = sizeof(address);
	char buffer[1024] = {0};
	char *hello = "Hello from server";

	// Creating socket file descriptor
	if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0)
	{
		perror("socket failed");
		exit(EXIT_FAILURE);
	}

    printf("Server:Server started\n");
	// Forcefully attaching socket to the port 8080
	if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT,&opt, sizeof(opt)))
	{
		perror("setsockopt");
		exit(EXIT_FAILURE);
	}
	address.sin_family = AF_INET;
	address.sin_addr.s_addr = INADDR_ANY;
	address.sin_port = htons( PORT );

	// Forcefully attaching socket to the port 8080
	if (bind(server_fd, (struct sockaddr *)&address, sizeof(address))<0)
	{
        printf("bind error\n");
		perror("bind failed");
		exit(EXIT_FAILURE);
	}
	if (listen(server_fd, 3) < 0)
	{
	    printf("listen error\n");
		perror("listen");
		exit(EXIT_FAILURE);
	}
	if ((new_socket = accept(server_fd, (struct sockaddr *)&address, (socklen_t*)&addrlen))<0)
	{
        printf("accept error\n");
		perror("accept");
		exit(EXIT_FAILURE);
	}
	valread = read( new_socket , buffer, 1024);
	printf("Server: %s\n",buffer );
	printf("Server: Reversing...\n" );
	send(new_socket , reverse(buffer) , strlen(buffer) , 0 );
	printf("Server: Reverced string message sent\n");
	return 0;
}