//server
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>typedef struct sockaddr SA;
int main(int argc,char **argv)
{int listenfd;    //也是以文件为操作，linux都是以文件为基础int confd;socklen_t clilen;struct sockaddr_in myaddr,cliaddr;char buf[50] = "Welcome";listenfd = socket(PF_INET,SOCK_STREAM,0)if(listenfd<0){perror("fail to connect");exit(-1);}//数据初始化bzero(&myaddr,sizeof(myaddr));myaddr.sin_family = PF_INET;myaddr.sin_addr.s_addr = inet_addr("192.168.1.1"); //ipmyaddr.sin_port = htons(8888); //端口号//绑定？ 为什么要强制转换？if(bind(listenfd,(SA *)&myaddr,sizeof(myaddr))<0){perror("fail to bind");exit(-1);}listen(listenfd,5);while(1){confd = accept(listenfd,(SA *)&cliaddr,sizeof(cliaddr));printf("connection from %s,port %d\n",inet_ntoa(cliaddr.sin_addr),ntohs(cliaddr.sin_port));send(connfd,buf,sizeof(buf),0);close(connfd);}return 0;
}

//client

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>typedef struct sockaddr SA;
int main(int argc,char **argv)
{int sockfd,nbyte;struct sockaddr_in servaddr,myaddr;char buf[50];sockfd = socket(PF_INET,SOCK_STREAM,0);if(sockfd<0){perror("fail to connect\n");exit(-1);}memset(0,&servaddr,sizeof(servaddr));servaddr.sin_family = PE_INET;servaddr.sin_addr.s_addr = inet_addr("192.168.1.1");  //server ipservaddr.sin_port = htons(8888);if(connect(sockfd,(SA *)&servaddr,sizeof(servaddr))<0){perror("connect error");exit(-1);}if((nbyte = recv(sockfd,buf,50,0))<0){perror("fail to recv");exit(-1);}printf("recv from server:%s\n", buf);return 0;
}