IP地址与主机名相互转换解析

#include <windows.h> #include <winsock.h> #include <stdio.h> #include <stdlib.h> #pragma comment(lib,"wsock32.lib") void choice(); void iptoname(); void nametoip(); DWORD Startup() { WSADATA wsaData; if(WSAStartup(MAKEWORD(1,1),&wsaData)!=0) { printf("Error:%d\n",WSAGetLastError); return -1; } return 1; } void iptoname() { char ip[64]; struct hostent *host; unsigned long lip; system("cls"); puts(" =======================\n"); puts(" IP=======>Name\n"); puts(" =======================\n"); printf("IP>"); scanf("%s",ip); fflush(stdin); lip=inet_addr(ip); host=gethostbyaddr((char*)&lip,4,AF_INET); if(host==NULL) printf("Error:%d\n",WSAGetLastError); printf("%s==>%s\n",ip,host->h_name); puts("-----------------------------------------"); puts("-=<任意键继续>=-"); getchar(); fflush(stdin); choice(); } void nametoip() { char name[64]; struct hostent *host; system("cls"); puts(" =======================\n"); puts(" Name======>IP\n"); puts(" =======================\n"); printf("DNS>"); scanf("%s",name); fflush(stdin); host=gethostbyname(name); if(host==NULL) printf("Error:%d\n",WSAGetLastError); printf("%s==>%s\n",name,inet_ntoa(*(struct in_addr*)(host->h_addr))); puts("-----------------------------------------"); puts("-=<任意键继续>=-"); getchar(); fflush(stdin); choice(); } void choice() { int i; system("cls"); puts("\n\t IP<-------->DNS"); puts("\t========================="); puts("\t| |"); puts("\t| 1.DNS------->IP |"); puts("\t| |"); puts("\t| 2.IP-------->DNS |"); puts("\t| |"); puts("\t| 3.quit |"); puts("\t| |"); puts("\t========================="); puts("\n=>Enter your choice"); scanf("%d",&i); fflush(stdin); if(i==1) nametoip(); else if(i==2) iptoname(); else if(i==3) return; else { puts("Input error!"); return; } } void main() { if(Startup()==-1) return; choice(); WSACleanup(); }