Linux网络编程(简单的时间获取服务器)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#include <netinet/in.h>
int main(int argc,char** argv)
{
    printf("服务器开启中\n");
    /*创建套接字*/
    int fd = socket(AF_INET,SOCK_DGRAM,0);
    if(-1 == fd)
    {
        perror("socket");
        exit(-1);
    }
    /*准备通信地址*/
    struct sockaddr_in addr;
    addr.sin_family = AF_INET;
    addr.sin_port   = htons(2222);
    addr.sin_addr.s_addr = inet_addr("172.16.1.21");
    /*防止端口被占用*/
    int reuse = 1;
    setsockopt(fd,SOL_SOCKET,SO_REUSEADDR,&reuse,sizeof(reuse));
    /*绑定网络端口和ip地址*/
    if(bind(fd,(struct sockaddr*)&addr,sizeof(addr)) == -1)
    {
        perror("bind");
        exit(-1);
    }
    while(1)
    {
        /*发送和接收消息*/
        char buf[100] = {};
        struct sockaddr_in from;
        /*创建一个当前的时间*/
        time_t now = time(0);
        struct tm* time = localtime(&now);
        socklen_t f_size = sizeof(from);
        recvfrom(fd,buf,sizeof(buf),0,(struct sockaddr*)&from,&f_size);
        printf("%s\n",buf);
        memset(buf,0,sizeof(buf));
        char str[50] = {};
        sprintf(str,"%04d-%02d-%02d %02d:%02d:%02d",time->tm_year+1900,
                     time->tm_mon+1,time->tm_mday,time->tm_hour,
                     time->tm_min,time->tm_sec);
        strcpy(buf,str);
        sendto(fd,buf,sizeof(buf),0,(struct sockaddr*)&from,sizeof(from));
        memset(buf,0,strlen(buf));
        memset(str,0,strlen(str));
    }
}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
int main(void)
{
    /*准备套接字*/
    int fd = socket(AF_INET,SOCK_DGRAM,0);
    if(-1 == fd)
    {
        perror("socket");
        exit(-1);
    }
    /*准备通信地址*/
    struct sockaddr_in addr;
    addr.sin_family = AF_INET;
    addr.sin_port = htons(2222);
    addr.sin_addr.s_addr = inet_addr("172.16.1.21");
    /*连接服务器的时候用sendto和UDP通信的时候可以不连接,直接发*/
    while(1)
    {
        char buf[50] = {};
        struct sockaddr_in from;
        socklen_t f_size = sizeof(from);
        scanf("%s",buf);
        if(-1 == sendto(fd,buf,strlen(buf),0,(struct sockaddr*)&addr,f_size))
        {
            perror("sendto");
            exit(-1);
        }
        memset(buf,0,strlen(buf));
        if(-1 == recvfrom(fd,buf,sizeof(buf),0,(struct sockaddr*)&from,&f_size))
        {
            perror("recvfrom");
            exit(-1);
        }
        printf("%s\n",buf);
        memset(buf,0,strlen(buf));

    }
    close(fd);
    return 0;
}