• Skip to primary navigation
  • Skip to content
  • Skip to primary sidebar
  • Skip to secondary sidebar

GoHired

Interview Questions asked in Google, Microsoft, Amazon

Join WeekEnd Online Batch from 4-April-2020 on How to Crack Coding Interview in Just 10 Weeks : Fees just 20,000 INR

  • Home
  • Best Java Books
  • Algorithm
  • Internship
  • Certificates
  • About Us
  • Contact Us
  • Privacy Policy
  • Array
  • Stack
  • Queue
  • LinkedList
  • DP
  • Strings
  • Tree
  • Mathametical
  • Puzzles
  • Graph

Client Server C program

November 28, 2015 by Dhaval Dave

Today we are going to show you to write simple C level Client – Server Networking & Communication program. This Program and methods are base to create any communication software like whatsapp, fb chat or other, because each connected terminal’s chat goes via server and then routed to device. So this is fist step for communication.

Step 1 : Understand Client Server Communication architecture from book

Step 2 : Run this client and Server code, modify and understand.

Step 3: Enjoy :)

Client Code 
__________________________
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define RAND_MAX 3

int main(int argc, char *argv[])
{
int sockfd;//client & Main Server
int c_len;
int i,j,rc;
char buff[100];
struct sockaddr_in c_address;
printf("**********This is the client program*************\n");

sockfd=socket(AF_INET, SOCK_STREAM,0);
c_address.sin_family = AF_INET;
c_address.sin_addr.s_addr = inet_addr("127.0.0.1");
c_address.sin_port = htons(7734);
c_len=sizeof(c_address);
rc=connect(sockfd, (struct sockaddr *)&c_address, c_len);
if(rc==1){
perror("Error in Client-Server Connect");
exit(0);
}
while(1){
printf("Enter Data(Buffer)\n");
gets(buff);

send(sockfd,buff,100,0);
}//while endeds
close (sockfd);
return(0);

}//main ended
Server Code
__________________________

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h> 

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define RAND_MAX 3

int main(int argc, char *argv[])
{

int s_sockfd, c_sockfd;//client & Main Server
int sc[4];//child servers pids
int sc_sockfd[4];//Child Server Socket IDs
int s_len, c_len;
int i,j,rc;
long int rand;
char buff[100];

struct sockaddr_in s_add;
struct sockaddr_in c_add;

if(s_sockfd=socket(AF_INET,SOCK_STREAM,0)<0)
 perror("Unable to create SOCKET :");

bzero((char *)&s_add,sizeof(s_add));
s_add.sin_family = AF_INET;
s_add.sin_addr.s_addr = htons(INADDR_ANY);
s_add.sin_port = htons(7766);
s_len=sizeof(s_add);


if(bind(s_sockfd, (struct sockaddr *) &s_add, s_len)<0)
 {
 perror("Error in ''Bind'' \n:");
 exit(0);
 }
if(listen(s_sockfd,10)<0)
 {
 perror("Error in ''Listen'' \n:");
 exit(0);
 }

for(i=0;i<4;i++)
 {
 sc[i]=fork();//four child server created;
 if(sc[i] < 0)
 perror("Error in Child server \n");
 }//e o for i<4 loop

while(1){
flag:
rand=random();//random numbers in the range from 0 to RAND_MAX
if(rand>3)
 goto flag;

if(sc[rand]==0){

 c_len = sizeof(c_add);
 c_sockfd = accept( sc[rand], (struct sockaddr *) &c_add, c_len);

 printf("After accept()");
 if(c_sockfd<0)
 {
 printf("Accept error\n");
 exit(0);
 }
 //close(s_sockfd);//dnt close it becuse child server will resend data to it
 
 dup2(c_sockfd,0);//std ip
 dup2(c_sockfd,1);//std op

 rc = recv(c_sockfd,buff,100,0);/*buff received from client*/
 
 printf("Received from client data => %s",buff);
 
 send(s_sockfd,buff,100,0);/*now resend it*/

}//if sc[r-1]==0 ended //child ended

}//while ended
rc = recv(sc[rand],buff,100,0); //received from child server
printf("Received at Main Server = >%s",buff);

close (s_sockfd);
return(0);
}//main ended

Similar Articles

Filed Under: Interview Questions, problem Tagged With: c

Reader Interactions

Primary Sidebar

Join WeekEnd Online/Offline Batch from 4-April-2020 on How to Crack Coding Interview in Just 10 Weeks : Fees just 20,000 INR

Join WeekEnd Online/Offline Batch from 4-April-2020

WhatsApp us

Secondary Sidebar

Custom Search

  • How I cracked AMAZON
  • LeetCode
  • Adobe
  • Amazon
  • Facebook
  • Microsoft
  • Hacker Earth
  • CSE Interview

Top Rated Questions

Find Pythagorean Triplets in an array in O(N)

Password Predictor

Stock Buy Sell to Maximize Profit

Possible sizes of bus to carry n groups of friends

Difference between a LinkedList and a Binary Search Tree BST

Find if two rectangles overlap

Flipkart Set 1 On Campus with Answers

How strtok() Works

Maximum of all subarrays of size k

Given Set of words or A String find whether chain is possible from these words or not

Test Cases for Round Function

Reliance Jio Software Developer Interview Experience

Regular Expression Matching

Binary Tree Isomorphic to each other

Word Break Problem

Number of Islands BFS/DFS

FizzBuzz Solution C C++

Find min element in Sorted Rotated Array (Without Duplicates)

Calculate price of parking from parking start end time prices

Find the element that appears once others appears thrice

Naurki.com Security Breach

The Magic HackerEarth Nirvana solutions Hiring Challenge

Hackerearth : Counting Subarrays

Skiing on Mountains Matrix

How Radix sort works

Find Nearest Minimum number in left side in O(n)

Convert number to words java

Python String and numbers

Wrong Directions given find minimum moves so that he can reach to the destination

Binary Tree in Java

Copyright © 2025 · Genesis Framework · WordPress · Log in