服务器端代码：

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

//服务器端
void main(int * argc, const char* argv[])
{

//创建监听套接字
int lfd = socket(AF_INET,SOCK_STREAM,0);
//绑定监听套接字
struct sockaddr_in serv;
memset(&serv,0,sizeof(serv));
serv.sin_family = AF_INET;
serv.sin_addr.s_addr = htonl(INADDR_ANY);
serv.sin_port = htons(6868);
bind(lfd,(struct sockaddr*)&serv, sizeof(serv));
//设置监听
listen(lfd, 36);
//等待并接收链接请求
struct sockaddr_in client;
socklen_t client_len = sizeof(client);
char buf[1024] = {0};
while (1)
{
printf(“server is ready listen\n”);
int cfd = accept(lfd,(struct sockaddr *)&client, &client_len);

    if(cfd == -1) {
        perror("accept error");
        exit(1);
    }

    //读数据
    while (1) {
        int len = read(cfd,&buf,sizeof(buf));
        if(-1 == len)
        {
            perror("read error\n");
            exit(1);
        }
        else if(0 == len)
        {
            printf("client close connect\n");
            break;
        }
        else{
            printf("client send data:%s\n",buf);
            //发送数据
            write(cfd,&buf,strlen(buf));
        }
        
        memset(buf,0,strlen(buf));
    }
}

//关闭套接字
close(lfd);
}

客户端代码：

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

int main(int * argc, const char * argv[])
{
//初始化通信套接字
int cfd = socket(AF_INET,SOCK_STREAM,0);
//初始化服务器地址信息
struct sockaddr_in serv;
memset(&serv,0,sizeof(serv));
serv.sin_family = AF_INET;
serv.sin_port = htons(6868);
inet_pton(AF_INET,“INADDR_ANY”,&serv.sin_addr.s_addr);

//链接服务器
connect(cfd,(const struct sockaddr *)&serv,sizeof(serv));


while (cfd != -1)
{
    //发送数据
    char buf[1024];
    printf("please input data\n");
    fgets(buf,sizeof(buf),stdin);
    write(cfd,&buf,strlen(buf));

    //接收数据
    int len = read(cfd,buf,sizeof(buf));
    if(-1 == len)
    {
        perror("read error\n");
        exit(1);
    }
    else if(0 == len)
    {
        printf("server close connect\n");
        break;
    }
    else{
        printf("recv data: %s\n", buf);
    }
}

//关闭套接字
close(cfd);

}

结果：