第一个TCP/IP程序

获取时间服务服务端

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

#define MAXLINE 4096
#define LISTENQ 1024

typedef  struct sockaddr SA;

int main(int argc, char *argv[]) {

    int listenfd, connfd;
    struct sockaddr_in servaddr;
    char buff[MAXLINE];
    time_t ticks;

    listenfd = socket(AF_INET, SOCK_STREAM, 0);

    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(9999);

    bind(listenfd, (SA *)&servaddr, sizeof(servaddr));

    listen(listenfd, LISTENQ);

    while (true) {

        connfd = accept(listenfd, (SA *)NULL, NULL);

        ticks = time(NULL);
        snprintf(buff, sizeof(buff), "%.24s\r\n", ctime(&ticks));
        write(connfd, buff, strlen(buff));
        std::cout << buff << std::endl;
        close(connfd);
    }
    return 0;
}

客户端

#include <iostream>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>

const int MAXLINE=4096;

typedef sockaddr SA;

int main(int argc, char ** argv) {

    int sockfd , n;

    char recvline[MAXLINE +1];

    struct sockaddr_in servaddr;

    if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0){
        std::cout << "socket error" <<std::endl;
    }
    bzero(&servaddr, sizeof(servaddr));

    servaddr.sin_family = AF_INET;
//
    servaddr.sin_port = htons(9999);

    if( inet_pton(AF_INET,argv[1],&servaddr.sin_addr) <= 0){
        std::cout << "inet_pton error for " << argv[1] << std::endl;
    }

    if(connect(sockfd,(sockaddr *)&servaddr, sizeof(servaddr)) < 0){
        std::cout << "connet error" <<std::endl;
    }

    while ((n = read(sockfd,recvline, MAXLINE)) > 0){
        recvline[n] = 0;
        if(fputs(recvline, stdout) == EOF)
            std::cout <<"Fputs error" << std::endl;
    }

    if (n < 0){
        std::cout << "read error" <<std::endl;
    }
    return 0;
}