Question

Q-1 write a client server program using tcp where client sends a string and server checks whether that string is palindrome or not and responds with appropriate message.

Answer 1

// defines in_addr structure

#include <arpa/inet.h>

// contains constants and structures

// needed for internet domain addresses

#include <netinet/in.h>

// standard input and output library

#include <stdio.h>

// contains string functions

#include <string.h>

// for socket creation

#include <sys/socket.h>

// contains constructs that facilitate getting

// information about files attributes.

#include <sys/stat.h>

// contains a number of basic derived types

// that should be used whenever appropriate

#include <sys/types.h>

main()

{

struct sockaddr_in client, server;

int s, n, sock, g, j, left, right, flag;

char b1[20], b2[10], b3[10], b4[10];

// creating socket

s = socket(AF_INET, SOCK_STREAM, 0);

// assign IP, PORT

server.sin_family = AF_INET;

// this is the port number of running server

server.sin_port = 2000;

server.sin_addr.s_addr = inet_addr("127.0.0.1");

// Binding newly created socket

// to given IP and verification

bind(s, (struct sockaddr*)&server, sizeof server);

listen(s, 1);

n = sizeof client;

sock = accept(s, (struct sockaddr*)&client, &n);

for (;;) {

recv(sock, b1, sizeof(b1), 0);

// whenever a request from a client came.

// It will be processed here.

printf("\nThe string received is:%s\n", b1);

if (strlen(b1) == 0)

flag = 1;

else {

left = 0;

right = strlen(b1) - 1;

flag = 1;

while (left < right && flag) {

if (b1[left] != b1[right])

flag = 0;

else {

left++;

right--;

}

}

}

send(sock, &flag, sizeof(int), 0);

break;

}

close(sock);

// close the socket

close(s);

}