通过网络在C中发送/接收数据

Question

我写了这个程序:

#include <sys/socket.h>
#include <sys/types.h>
#include <netdb.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>

int socket_desc;
struct sockaddr_in adress;
int addrlen;
int new_socket;
int bufsize = 1024;

char *you_sent = "You sent: ";

int main() {
    char *buffer = malloc(bufsize);
    socket_desc = socket(AF_INET, SOCK_STREAM, 0);
    adress.sin_family = AF_INET;
    adress.sin_addr.s_addr = INADDR_ANY;
    adress.sin_port = htons(7000);
    bind(socket_desc, (struct sockaddr *)&adress, sizeof(adress));
    listen(socket_desc, 3);
    addrlen = sizeof(struct sockaddr_in);
    new_socket = accept(socket_desc, (struct sockaddr *)&adress, &addrlen);
    while(recv(new_socket,buffer,bufsize,0))
    {
        printf("I recieved: %s", buffer);
        send(new_socket, you_sent, strlen(you_sent), 0);
        send(new_socket, buffer, strlen(buffer), 0);
        memset(buffer, '\0', sizeof(buffer));
    }
}

我可以使用telnet连接到服务器.并将内容写入应用程序并从应用程序中接收数据.但我无法理解如何使用另一个c程序连接到此程序,并从该程序发送和接收数据.我试过这个:

#include <sys/socket.h>
#include <sys/types.h>
#include <netdb.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>

int socket_desc;
struct sockaddr_in adress;
int addrlen;
int new_socket;

char *message_to_send = "Hello world!";

int main() {
    socket_desc = socket(AF_INET, SOCK_STREAM, 0);
    adress.sin_family = AF_INET;
    adress.sin_addr.s_addr = INADDR_ANY;
    adress.sin_port = htons(7000);
    bind(socket_desc, (struct sockaddr *)&adress, sizeof(adress));
    listen(socket_desc, 3);
    addrlen = sizeof(struct sockaddr_in);
    new_socket = accept(socket_desc, (struct sockaddr *)&adress, &addrlen);
    send(new_socket, message_to_send, strlen(message_to_send), 0);
}

Answer 1

服务器就像交换机板上的电话运营商.那个人做了以下事情:

• 坐在电话前(即bind一个号码)
• 等待它响起(即listen)
• 拿起电话(即accept)

另一端的人只是想打电话给那个人.(即connect).当需要打电话时,此人只需要打电话.因此没有绑定到手机或不得不听它响.

我希望这个比喻有助于你的理解.

PS:socket部分是墙上的电话插座.