/** =====================================================================================**       Filename:  ipconverter.cpp**    Description:  **        Version:  1.0*        Created:  01/08/2012 11:02:12 PM*       Revision:  none*       Compiler:  gcc**         Author:  gnuhpc (http://www.cnblogs.com/gnuhpc), warmbupt@gmail.com*        Company:  CMBC** =====================================================================================*/
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>using namespace std;char* itoa(int i)
{char* temp = new char(6);sprintf(temp,"%d",i);return temp;
}char* numToIP1(unsigned int num)
{char* buf = new char[sizeof("aaa.bbb.ccc.ddd")];unsigned char* p = (unsigned char *)&num;sprintf(buf, "%d.%d.%d.%d", p[3]&0xff,p[2]&0xff,p[1]&0xff,p[0]&0xff);return buf;
}
char* numToIP2(unsigned int num)
{char* buf = new char[sizeof("aaa.bbb.ccc.ddd")];for(int i=3;i>=0;i--){strcat(buf, itoa((num>>8*i)&0xff));if(i!=0)strcat(buf,".");}return buf;
}unsigned int ipToNum(char* ip)
{char* p;int sections[4]={0};int i=0;p = strtok(ip,".");while( p ){sections[i] = atoi(p);p = strtok(NULL,".");cout << sections[i] << endl;i++;}unsigned int num =0;for( int j=3,i=0 ; j>=0 ; j--,i++ ){num += (sections[i] <<(8*j));}return num;
}int main(){char* p = numToIP1(167773121);cout << p << endl;delete p;p = numToIP2(167773121);cout << p << endl;delete p;char ip[16] = "10.0.3.193";cout << ipToNum(ip) << endl;return 0;
}

package cnblogs.gnuhpc.ipconvertor;public class IPConvertor {public static String numToIP(long ip){StringBuilder sb = new StringBuilder();for (int i = 3; i >=0; i--) {sb.append((ip>>>(i*8))&0x000000ff);if (i!=0) {sb.append('.');}}System.out.println(sb);return sb.toString();}public static long ipToNum(String ip){long num = 0;String[] sections = ip.split("\\.");int i=3;for (String str : sections) {num+=(Long.parseLong(str)<<(i*8));i--;}System.out.println(num);return num;}
}