伺服器端程式碼：

#include<stdio.h>
#include<string.h>
#include<errno.h>
#include<sys/socket.h>
#include<resolv.h>
#include<stdlib.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<unistd.h>
#include<fcntl.h>   
 
int main (int argc, char * argv[])  
{  
    //建立套接字,即建立socket   
    int server_sockfd, client_sockfd;
    unsigned  int myport;
    socklen_t len;
    struct sockaddr_in server_addr, client_addr;
    char buf[1024];  
    //繫結資訊，即命名socket    
    server_addr.sin_family = AF_INET;   
    server_addr.sin_port = htons(myport);
        
        if (argc !=3 )
    {
        printf("Please Input %s  IP Port\n",argv[0]);
        exit(EXIT_FAILURE);    
    }
    //inet_addr函式將用點分十進位制字串表示的IPv4地址轉化為用網路位元組序整數表示的IPv4地址
    if(argv[1])
        server_addr.sin_addr.s_addr = inet_addr(argv[1]);
    else
        server_addr.sin_addr.s_addr = INADDR_ANY;
    if(argv[2])
        myport = atoi(argv[2]);
    else
        myport = 7575;
 
    //建立socket
    if((server_sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)  
    {        
         perror("socket");  
         return 1;  
    }  
 
     //繫結
    if(bind(server_sockfd, (struct sockaddr*)&server_addr, sizeof(server_addr)) < 0)   
    {                           
        perror("bind");   
        return 2;         
    }   
 
        //監聽socket   
    if(listen(server_sockfd, 5) < 0)  
    {    
        perror("listen");  
        return 3;  
    }  
 
        
      //int accept(int sockfd, struct sockaddr* addr, socklen_t* addrlen)  
      //sockfd引數是執行過listen系統呼叫的監聽socket；addr引數用來獲取被  
      //接受連線的遠端socket地址，該socket地址的長度由addrlen引數指出  
      //accept成功時返回一個新的連線socket，該socket唯一的標識了被接受  
      //的這個連線，伺服器可通過讀寫該socket來與被接受連線對應的客戶端通訊    
 
      len = sizeof(struct sockaddr);
      client_sockfd = accept(server_sockfd, (struct sockaddr*)&client_addr, (socklen_t *)&len);  
 
      if(client_sockfd < 0)  
      {  
          perror("accept");  
          return 4;  
      }  
      else  
      {  
          printf("connected with IP: %s  and port: %d\n", inet_ntop(AF_INET,&client_addr.sin_addr, buf, 1024), ntohs(client_addr.sin_port));  
          
      }  
    printf("Waiting client connecting……");
      while(1)  
      {  
          memset(buf, '\0', sizeof(buf));  
          ssize_t size = read(client_sockfd, buf, sizeof(buf) - 1);  
 
          if(size > 0)  
          {  
              printf("client#: %s\n", buf);  
          }  
          else if(size == 0)  
          {  
              printf("read is done...\n");  
              break;  
          }  
          else   
          {  
              perror("read");  
              break;  
          }  

          printf("server please enter: ");  
          fflush(stdout);  //重新整理標準輸出緩衝區，把輸出緩衝區裡的東西列印到標準輸出裝置上
          size = read(0, buf, sizeof(buf) - 1);  
          if(size > 0)  
          {  
              buf[size - 1] = '\0';  
          }  
          else if(size == 0)  
          {  
              printf("read is done...\n");  
              break;  
          }  
          else  
          {  
              perror("read");  
              break;  
          }     
          write(client_sockfd, buf, strlen(buf));  
      }  
        close(server_sockfd);  
      return 0;  
} 

客戶端程式碼：

#include <stdio.h>  
#include <string.h>  
#include <stdlib.h>  
#include <sys/types.h>  
#include <sys/socket.h>  
#include <sys/un.h>  
#include <arpa/inet.h>  
#include <netinet/in.h>  

int main (int argc, char * argv[])  
{  
    unsigned int myport;
    int client_sockfd;
      //建立套接字,即建立socket   

        if (argc !=3 )
    {
        printf("Please Input %s  IP Port\n",argv[1]);
        exit(EXIT_FAILURE);    
    }

       client_sockfd = socket(AF_INET, SOCK_STREAM, 0);   
      if(client_sockfd < 0)  
      {  
          perror("socket");  
          return 1;  
      }  
 
      //繫結資訊，即命名socket   
      struct sockaddr_in addr;   
      addr.sin_family = AF_INET;   
      addr.sin_port = htons(atoi(argv[2]));   
      //inet_addr函式將用點分十進位制字串表示的IPv4地址轉化為用網路   
      //位元組序整數表示的IPv4地址   
      addr.sin_addr.s_addr = inet_addr(argv[1]);   
 
      //不需要監聽  
 
      //發起連線  
//    struct sockaddr_in peer;  
      socklen_t addr_len = sizeof(addr);  
      int connect_fd = connect(client_sockfd, (struct sockaddr*)&addr, addr_len);  
      if(connect_fd < 0)  
      {  
          perror("connect");  
          return 2;  
      }  
      char buf[1024];  
 
      while(1)  
      {  
          memset(buf, '\0', sizeof(buf));  
          printf("client please enter: ");  
          fflush(stdout);  
          ssize_t size = read(0, buf, sizeof(buf) - 1);  
          if(size > 0)  
          {  
              buf[size - 1] = '\0';  
          }  
          else if(size == 0)  
          {  
              printf("read is done...\n");  
              break;  
          }  
          else  
          {  
              perror("read");  
              return 4;  
          }  
         // printf("client: %s\n", buf);  
          write(client_sockfd, buf, strlen(buf));  
          size = read(client_sockfd, buf, sizeof(buf));  
          if(size > 0)  
          {  
              buf[size] = '\0';  
          }  
          else if(size == 0)  
          {  
              printf("read is done...\n");  
              break;  
          }  
          else   
          {  
              perror("read");  
              return 5;  
          }  
          printf("server: %s\n", buf);  
       }  
      close(client_sockfd);  
      return 0;  
}