UDP Server-Client Chat Implementation in C

UDP Server

Source code:= https://github.com/shouvik126/Networking-UDP-chat-

//Programme for UDP server

#include<stdio.h>
#include<string.h>
#include <sys/types.h>     
#include <sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<unistd.h>
#include<netdb.h>
#include<fcntl.h>
#define PORT_NUM 1500  //port number on which message will recieve and send
int i=1;
int main()
{
 int sock;      //variable for socket descriptor(server)
 int len;       //variable for initialize structure length
 char out_buf[100],in_buf[100];   //variable for input and output message initialize

 struct sockaddr_in server,client;
 
 sock=socket(AF_INET,SOCK_DGRAM,0);       //socket descripter for server(using ipv4)
 server.sin_family=AF_INET;
 server.sin_port=htons(PORT_NUM);         //host to network short byte word
 server.sin_addr.s_addr=htonl(INADDR_ANY);//host to network long byte order
 len=sizeof(struct sockaddr_in);          //storing length of structure (define below)
 bind(sock,(struct sockaddr*)&server,len);//binding the socket with port num and ip

 printf("server is waiting.....\n");        //server goes to listen mode(explicitely define in tcp server)

 while(1)
 {
  recvfrom(sock,in_buf,sizeof(in_buf),0,(struct sockaddr *)&client,&len);//recieve byte by byte stream from client 
                if(i==1)    //at 'in_buf' through server socket 
  {
   printf("\nrequest accepted.................\n");
  }
  printf("\nrecieve from client...message:=%s\n",in_buf);    //display message recieve from client
         printf("\n\tEnter Message:=");
  scanf ("%[^\n]%*c",out_buf);//input along with space
  sendto(sock,out_buf,(strlen(out_buf)+1),0,(struct sockaddr *)&client,len);//stream send to client through socket
                                                                                  //(here length is increase by 1 because to assign null                                                                                        //explicitely at the end of the stream 'out_buf')
  i++;
 }
 close(sock); 
}

Screenshot

UDP Client 

Source code:= https://github.com/shouvik126/Networking-UDP-chat-

//programmme for udp client
#include<stdio.h>
#include<string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<unistd.h>
#include<netdb.h>
#include<fcntl.h>
#define PORT_NUM 1500  //port number on which message will recieve and send
#define SERVER_IP "127.127.127.127"//loop back address as i am using same system for botth server and client

int main()
{
 int sock;  //variable for socket descriptor(client)
 int len;   //variable for initialize structure length
 char out_buf[100],in_buf[100];  //variable for input and output message initialize
 
 struct sockaddr_in server;        //server address is required by client but viceversa is not needed
 sock=socket(AF_INET,SOCK_DGRAM,0);//socket descripter for server(using ipv4)
 server.sin_family=AF_INET;
 server.sin_port=htons(PORT_NUM);  //host to network short byte word
 server.sin_addr.s_addr=inet_addr(SERVER_IP);//function 'inet_addr()' converts  the Internet host address cp from
                                                    // IPv4 numbers-and-dots notation into binary data in network byte  order.

 len=sizeof(struct sockaddr_in);    //storing length of structure (define below)
 //strcpy(out_buf,"hey server i am connecting with you..");//storing stream at out_buf for sending to server
 while(1)
 {
  printf("\n\tEnter MEssage:=");
  scanf("%[^\n]%*c",out_buf);
  sendto(sock,out_buf,(strlen(out_buf)+1),0,(struct sockaddr *)&server,len);//stream send to client through socket
                                                                                   //(here length is increase by 1 because to assign null 
             //explicitely at the end of the stream 'out_buf')

  recvfrom(sock,in_buf,sizeof(in_buf),0,(struct sockaddr *)&server,&len);  //recieve byte by byte stream from client 
            //at 'in_buf' through server socket
  printf("recieve from server message:=%s\n",in_buf);
 }
 close(sock);


}

Screenshot