socket programming in c++

client.cpp

#include <cstdio>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <iostream>


using namespace std;

void msg(const char *msg){

	perror(msg);
	exit(0);
}


int readLine(int fd, char *buf, size_t n)
{
	int s=0;
	char ch;
   do{
        s++;    
        if(read(fd,&ch,1)>0)
        {
        	*buf++ = ch;
        }   

     } 	
    while(ch!='\n' && s<n);

    *buf='\0';

    return s;
   
}

class hkclient{
   
    int s_skt_fd;
    int port;
    struct hostent *server;
    struct sockaddr_in serv_addr; 
    public:
    
       hkclient(char *argv[]){
             
             
             port=atoi(argv[2]);
             s_skt_fd=socket(AF_INET,SOCK_STREAM,0);

             if(s_skt_fd<0) msg("error opening socket"); 

             server=gethostbyname(argv[1]); 

             if(server<0) msg("error no such host"); 
             serv_addr.sin_family=AF_INET;
             bcopy((char *)server->h_addr,(char *)&serv_addr.sin_addr.s_addr,server->h_length);
             serv_addr.sin_port=htons(atoi(argv[2]));

            cout<<"sockt regist";
       }


       void conct(){

             int b=connect(s_skt_fd,(struct sockaddr *)&serv_addr,sizeof(serv_addr));

             if(b<0) msg("Error on connecting");

       } 

     void sendMsg(const char *s){
        
         int n=write(s_skt_fd,s,strlen(s));
         if(n<0) msg("error in writing msg");

      } 


    char * getMsg(){
         
         char buffer[1024];
         int n=readLine(s_skt_fd,buffer,1024);
         if(n<0) msg("error in reading msg");    

         return &buffer[0];            
    }

  

};


int main(int argc,char *argv[]){ // arg(2)->ip port

  if(argc<3){msg("argument is ip and port");exit(0);}


  hkclient c(argv);

  c.conct();

  
  c.sendMsg("i am hitesh\n");
  cout<<c.getMsg();
  

}

server.cpp

#include <cstdio>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <iostream>


using namespace std;

void error(const char *msg){

	perror(msg);
	exit(0);
}


int readLine(int fd, char *buf, int n)
{
	int s=0;
	char ch;
   do{
        s++;    
        if(read(fd,&ch,1)==1)
        {
        	*buf++ = ch;
        }   

     } 	
    while(ch!='\n' && s<n);

    *buf='\0';
   

    return s;
}

class hkserver{

  int s_skt_fd;
  int c_skt_fd;
  int port;
  socklen_t clilen;
  struct sockaddr_in serv_addr,cli_addr;
  int qlength;
 
public:
	   hkserver(int p)
	   {
          port=p;
          qlength=10;  
          s_skt_fd=socket(AF_INET,SOCK_STREAM,0);
          
          if(s_skt_fd<0)
                error("error opening sockdt");

          serv_addr.sin_family=AF_INET;
          serv_addr.sin_addr.s_addr=INADDR_ANY;
          serv_addr.sin_port=htons(port);        
         
           int b=bind(s_skt_fd,(struct sockaddr *)&serv_addr,sizeof(serv_addr));

           if(b<0) error("error on binding");         

	   }


	   void start(){

              listen(s_skt_fd,qlength);
               
               clilen=sizeof(cli_addr);
               c_skt_fd=accept(s_skt_fd,(struct sockaddr *)&cli_addr,&clilen);

               if(c_skt_fd<0) error("error on accepting");

           }


      void sendMsg(const char *s){
           
         int n=write(c_skt_fd,s,strlen(s));
         
         if(n<0) error("error in writing msg");

      } 


    char * getMsg(){
         
         char buffer[1024];
        
        int n=readLine(c_skt_fd,buffer,1024);
        
        if(n<0) error("error in reading msg");

        return &buffer[0];                 
    }

   ~hkserver()
   {

   	close(s_skt_fd);
   	close(c_skt_fd);
   }


 





};



int main(int argc,char *argv[]){ // arg(1)->port

   

   hkserver s(atoi(argv[1]));

   s.start();

   string msg=s.getMsg();

   cout<<"new clinet:"<<msg;

   s.sendMsg("hello! I am aditi\n");




}