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用域名获取IP地址或者用IP获取域名
#include#include #include int main(int argc,char **aggv){ struct hostent *host; char hostname[]="www.163.com"; char hostname2[]="www.baidu.com"; struct in_addr in; struct sockaddr_in addr_in; int h_errno; char addr[]="202.108.249.216"; if((host=gethostbyname(hostname))!=NULL) { memcpy(&addr_in.sin_addr.s_addr,host->h_addr,4); in.s_addr=addr_in.sin_addr.s_addr; printf("Domain name : %s \n",hostname); printf("IP length is: %d \n",host->h_length); printf("Type : %d \n",host->h_addrtype); printf("IP : %s \n",inet_ntoa(in)); } if(((host=gethostbyaddr(addr,sizeof(addr),AF_INET)))!=(struct hostnet *)NULL) { memcpy(&addr_in.sin_addr.s_addr,host->h_addr,4); in.s_addr=addr_in.sin_addr.s_addr; printf("\n---------------------\n"); printf("Domain name : %s \n",hostname); printf("IP length is: %d \n",host->h_length); printf("Type : %d \n",host->h_addrtype); printf("IP : %s \n",inet_ntoa(in)); } return 0;}
#include#include #include int main(){ int i ; for(i=0;i<6;i++) printf("%d %s \n",i,hstrerror(i));//捕获错误编号 char cp[]="192.168.0.84"; printf("%ld\n",inet_addr(cp)); //将网络地址转换成整型 struct in_addr ip; ip.s_addr=16885952; printf("%s\n",inet_ntoa(ip)); //将整型转换成网络地址 long local; int port; local=123456; port=1024; printf("net: %d\n",htonl(local));//主机字符顺序与网络字节顺序的转换 printf("net: %d\n",htonl(port)); printf("local: %d\n",ntohl(htonl(local))); printf("local: %d\n",ntohl(htonl(port))); return 0;}
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