#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/shm.h>
#include <thread>
#include <iostream>
#define PORT 7000
#define QUEUE 20
int conn;
void thread_task() {
}

int main() {
    //printf("%d\n",AF_INET);
    //printf("%d\n",SOCK_STREAM);
    int ss = socket(AF_INET, SOCK_STREAM, 0);
    //printf("%d\n",ss);
    struct sockaddr_in server_sockaddr;
    server_sockaddr.sin_family = AF_INET;
    server_sockaddr.sin_port = htons(PORT);
    //printf("%d\n",INADDR_ANY);
    server_sockaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    if(bind(ss, (struct sockaddr* ) &server_sockaddr, sizeof(server_sockaddr))==-1) {
        perror("bind");
        exit(1);
    }
    if(listen(ss, QUEUE) == -1) {
        perror("listen");
        exit(1);
    }

    struct sockaddr_in client_addr;
    socklen_t length = sizeof(client_addr);
    ///成功返回非负描述字，出错返回-1
    conn = accept(ss, (struct sockaddr*)&client_addr, &length);
    if( conn < 0 ) {
        perror("connect");
        exit(1);
    }

    char buffer[1024];
    //创建另外一个线程
    //std::thread t(thread_task);
    //t.join();
    //char buf[1024];
    //主线程
    while(1) {

        // memset(buf, 0 ,sizeof(buf));
        // if(fgets(buf, sizeof(buf),stdin) != NULL) {
        //     send(conn, buf, sizeof(buf), 0);    
        // }

        memset(buffer, 0 ,sizeof(buffer));
        int len = recv(conn, buffer, sizeof(buffer), 0);
        if(strcmp(buffer, "exit\n") == 0) break;
        printf("%s", buffer);
        //必须要有返回数据， 这样才算一个完整的请求
        send(conn, buffer, len , 0);
    }
    close(conn);
    close(ss);
    return 0;
}　　

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

#define MYPORT  7000
#define BUFFER_SIZE 1024

int main()
{
    ///定义sockfd
    int sock_cli = socket(AF_INET,SOCK_STREAM, 0);

    ///定义sockaddr_in
    struct sockaddr_in servaddr;
    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(MYPORT);  ///服务器端口
    servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");  ///服务器ip

    //连接服务器，成功返回0，错误返回-1
    if (connect(sock_cli, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0)
    {
        perror("connect");
        exit(1);
    }

    char sendbuf[BUFFER_SIZE];
    char recvbuf[BUFFER_SIZE];
    while (fgets(sendbuf, sizeof(sendbuf), stdin) != NULL)
    {
        send(sock_cli, sendbuf, strlen(sendbuf),0); ///发送
        if(strcmp(sendbuf,"exit\n")==0)
            break;
        recv(sock_cli, recvbuf, sizeof(recvbuf),0); ///接收
        fputs(recvbuf, stdout);

        memset(sendbuf, 0, sizeof(sendbuf));
        memset(recvbuf, 0, sizeof(recvbuf));
    }

    close(sock_cli);
    return 0;
}