如何使用c socket发送和接收数据？

Question

我正在学习c中的套接字，我想从服务器写套接字在客户端读取它，而不是从客户机写以供服务器读取。但是我的程序卡住了。我知道套接字是二维的，但是我无法运行此代码。为什么要屏蔽此代码？我该如何解决？

我想做的概念（在while循环中）

  server        client
  read          write
  write         read

服务器代码

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

int main(int argc, char *argv[])
{
int listenfd = 0, connfd = 0;
struct sockaddr_in serv_addr;

char sendBuff[1025];
time_t ticks;

/* creates an UN-named socket inside the kernel and returns
 * an integer known as socket descriptor
 * This function takes domain/family as its first argument.
 * For Internet family of IPv4 addresses we use AF_INET
 */
listenfd = socket(AF_INET, SOCK_STREAM, 0);
memset(&serv_addr, '0', sizeof(serv_addr));
memset(sendBuff, '0', sizeof(sendBuff));

serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
serv_addr.sin_port = htons(5000);

/* The call to the function "bind()" assigns the details         specified
 * in the structure 『serv_addr' to the socket created in the step above
 */
bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));

/* The call to the function "listen()" with second argument as 10 specifies
 * maximum number of client connections that server will queue for this listening
 * socket.
 */
listen(listenfd, 10);

while(1)
{
    /* In the call to accept(), the server is put to sleep and when for an incoming
     * client request, the three way TCP handshake* is complete, the function accept()
     * wakes up and returns the socket descriptor representing the client socket.
     */
    connfd = accept(listenfd, (struct sockaddr*)NULL, NULL);

    /* As soon as server gets a request from client, it prepares the date and time and
     * writes on the client socket through the descriptor returned by accept()
     */
    ticks = time(NULL);
    snprintf(sendBuff, sizeof(sendBuff), "%.24s\r\n", ctime(&ticks));
    write(connfd, sendBuff, strlen(sendBuff));
    int n=0;
    while ( (n = read(connfd, sendBuff, sizeof(sendBuff)-1)) > 0)
{
    sendBuff[n] = 0;
    if(fputs(sendBuff, stdout) == EOF)
    {
        printf("\n Error : Fputs server error\n");
    }

}
    close(connfd);
    sleep(1);
}
}

还有我的客户代码

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

int main(int argc, char *argv[])
{
int sockfd = 0, n = 0;
char recvBuff[1024];
struct sockaddr_in serv_addr;

if(argc != 2)
{
    printf("\n Usage: %s <ip of server> \n",argv[0]);
    return 1;
}

memset(recvBuff, '0',sizeof(recvBuff));

/* a socket is created through call to socket() function */
if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
{
    printf("\n Error : Could not create socket \n");
    return 1;
}

memset(&serv_addr, '0', sizeof(serv_addr));

serv_addr.sin_family = AF_INET;
serv_addr.sin_port = htons(5000);

if(inet_pton(AF_INET, argv[1], &serv_addr.sin_addr)<=0)
{
    printf("\n inet_pton error occured\n");
    return 1;
}

/* Information like IP address of the remote host and its port is
 * bundled up in a structure and a call to function connect() is made
 * which tries to connect this socket with the socket (IP address and port)
 * of the remote host
 */
if( connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0)
{
    printf("\n Error : Connect Failed \n");
    return 1;
}

/* Once the sockets are connected, the server sends the data (date+time)
 * on clients socket through clients socket descriptor and client can read it
 * through normal read call on the its socket descriptor.
 */
while ( (n = read(sockfd, recvBuff, sizeof(recvBuff)-1)) > 0)
{
    recvBuff[n] = 0;
    if(fputs(recvBuff, stdout) == EOF)
    {
        printf("\n Error : Fputs error\n");
    }

}

write(sockfd, "example", strlen("example"));

if(n < 0)
{
    printf("\n Read error \n");
}

return 0;
}