修改后 简单的 UDP server

/*
 ============================================================================
 Name        : UDPserver.c
 Author      : vestinfo
 Version     : 1.1
 Copyright   : www.cnblogs.com/vestinfo
 Description : A simple UDP server, Ansi-style
 ============================================================================
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/socket.h>

#define LOCALPORT 8888

#define MAXLENGTH 256

int main(int argc,char *argv[])
{
	int sockfd;
	char msg[MAXLENGTH];
	struct sockaddr_in servaddr;
	struct sockaddr_in cliaddr;
	socklen_t addr_len;
	addr_len = sizeof(cliaddr);

	/* 创建套接字 */
	if((sockfd = socket(AF_INET,SOCK_DGRAM,0)) < 0)
	{
		perror("error");
		exit(1);
	}

	/* 绑定server的端口 */
	bzero(&servaddr,sizeof(servaddr));
	servaddr.sin_family = AF_INET;
	servaddr.sin_port = htons(LOCALPORT);
	servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
	if(bind(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0)
	{
		perror("error");
		exit(1);
	}
	
	printf("UDP server waiting for client...\n");

	while(1)
	{
		bzero(msg, MAXLENGTH);
		recvfrom(sockfd, msg, MAXLENGTH, 0, (struct sockaddr *)&cliaddr, &addr_len);	//接收来自client的msg

		printf("Received message from:%s\n",inet_ntoa(cliaddr.sin_addr));
		printf("The message Received from client:%s",msg);

		sendto(sockfd, msg, sizeof(msg), 0, (struct sockaddr *)&cliaddr, addr_len);	//发送msg给client
	}
}