tcpechoserver.c
#include<stdio.h>
#include<sys/types.h>
#include<string.h>
#include<stdlib.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<unistd.h>
#define SA struct sockaddr
#define LISTENQ 5
int main(int argc,char **argv)
{
int fd,sockfd,listenfd,connfd;
pid_t childpid;
socklen_t client;
struct sockaddr_in Servaddr,cliaddr;
listenfd=socket(AF_INET,SOCK_STREAM,0);
bzero(&Servaddr,sizeof(Servaddr));
Servaddr.sin_family=AF_INET;
Servaddr.sin_addr.s_addr=htonl(INADDR_ANY);
Servaddr.sin_port=htons(atoi(argv[1]));
bind(listenfd,(SA*)&Servaddr,sizeof(Servaddr));
listen(listenfd,LISTENQ);
client=sizeof(cliaddr);
connfd=accept(listenfd,(SA*)&cliaddr,&client);
char buffer[100],buf[100];
printf("\n The received from client content");
read(connfd,buffer,100);
printf("%s",buffer);
strcpy(buffer,buf);
write(connfd,buf,100);
printf("\n The content is echod");
}

tcpechoclient.c
#include<stdio.h>
#include<sys/types.h>
#include<string.h>
#include<stdlib.h>
#include<stdio.h>
#include<sys/types.h>
#include<string.h>
#include<stdlib.h>
#include<stdio.h>
#include<sys/types.h>
#include<string.h>
#include<stdlib.h>
#include<arpa/inet.h>
#include<unistd.h>
#define SA struct sockaddr
int main(int argc,char **argv)
{
int sockfd;
char fname[25];
int len;
struct sockaddr_in servaddr,cliaddr;
sockfd=socket(AF_INET,SOCK_STREAM,0);
bzero(&servaddr,sizeof(servaddr));
servaddr.sin_family=AF_INET;
servaddr.sin_addr.s_addr=htonl(INADDR_ANY);
servaddr.sin_port=htons(atoi(argv[1]));
inet_pton(AF_INET,argv[1],&servaddr.sin_addr);
connect(sockfd,(SA*)&servaddr,sizeof(servaddr));
char buffer[100],buf[100];
printf("\n Enter connect 2 echo");
scanf("%s",buffer);
write(sockfd,buffer,100);
printf("\n The content is sent \n");
read(sockfd,buf,100);
printf("\n The echod content %s",buffer);
}