服务端：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <netinet/in.h>
#include <sys/types.h>#include <errno.h>int main(void)
{//1.socketint server_sock = socket(AF_INET, SOCK_STREAM, 0);// addressstruct sockaddr_in server_addr;server_addr.sin_addr.s_addr = INADDR_ANY;server_addr.sin_port = htons(9001);server_addr.sin_family = AF_INET; //2.bindif ( (bind(server_sock, (struct sockaddr*) &server_addr, sizeof(server_addr))) != 0 ){fprintf(stderr, "couldn't bind: %s\n", strerror(errno));exit(EXIT_FAILURE);}//3.listenif ((listen(server_sock, 10)) != 0){fprintf(stderr, "couldn't listen: %s\n", strerror(errno));exit(EXIT_FAILURE);}int client_sock;//4.acceptif( (client_sock = accept(server_sock, NULL, NULL)) == -1 ){fprintf(stderr, "couldn't accept: %s\n", strerror(errno));exit(EXIT_FAILURE);}char send_message[255] = "hello i am server";send(client_sock, send_message, sizeof(send_message), 0);char buf[256];recv(client_sock,buf,sizeof(buf),0);printf("Server recv:%s\n",buf);close(server_sock);close(client_sock);return 0;
}

客户端：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>#include <netinet/in.h>#include <errno.h>int main(void){//1.create sockint sock = socket(AF_INET, SOCK_STREAM, 0);if(sock < 0){fprintf(stderr, "can't create socket because of %s\n", strerror(errno));exit(EXIT_FAILURE);}//create addressstruct sockaddr_in server_addr;server_addr.sin_addr.s_addr = INADDR_ANY;server_addr.sin_port = htons(9001);server_addr.sin_family = AF_INET;//connectif( (connect(sock, (struct sockaddr*)&server_addr, sizeof(server_addr))) == -1  ){perror("connect error because of: ");close(sock);exit(EXIT_FAILURE);}//create recv buffer and recvchar recv_buffer[255];recv(sock, recv_buffer, sizeof(recv_buffer), 0);//printprintf("printf recv: %s\n", recv_buffer);char send_message[255] = "I Love China!";send(sock, send_message, sizeof(send_message), 0);close(sock);return 0;
}

结果：