本文內容提到的套接字都是Berkely socket.

實用套接字的四個步驟:
1 分配空間和初始化
2 連線
3 傳送資料
4 關閉

具體演算法:

伺服器端:
#include <sys/socket.h>
#include <netinet/in.h>

int socket_descriptor;
socket_descriptor = socket(AF_INET, SOCK_STREAM, 0);

int port = 8000;
struct sockaddr_in sin;
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = INADDR_ANY;
pin.sin_port = htons(port);

bind(socket_descriptor,(struct socketaddr *)&sin, sizeof(sin) );

listen(socket_descriptor, 1024);

struct sockaddr_in pin;
int address_size;
int temp_socket_descriptor;

while(1) {
  temp_socket_descriptor = accept(socket_descriptor,(struct socketaddr *)&pin,  sizeof(address_size));
  ......
  close(temp_socket_descriptor);
}


客戶端:
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>     //直接影響sockaddr_in.sin_addr的填寫

char * host_name = "127.0.0.1";
struct hostent * server_host_name;
server_host_name = gethostbyname(host_name);

int port = 8000;
struct sockaddr_in pin;
pin.sin_family = AF_INET;
pin.sin_addr.s_addr = htol(INADDR_ANY);
pin.sin_addr.s_addr = ((struct in_addr *)(server_host_name->h_addr))->s_addr; 或者 pin.sin_addr = *(struct in_addr *) server_host_name->h_addr;
pin.sin_port = htons(port);

int socket_descriptor;
socket_descriptor = socket(AF_INET, SOCK_STREAM, 0);
connect(socket_descriptor, (void *)&pin, sizeof(pin));
.......
close(socket_descriptor);