IP和整数的相互转换

#include <stdio.h>

#include <string.h>

#include <string>

#include <iostream>

using namespace std;

char strTemp[20];

char* numbertoIp(unsigned long nValue)

{

//    static char szAddr[16] = {0};

//    unsigned long ulMask[4] = {0x000000FF, 0x0000FF00, 0x00FF0000, 0xFF000000};

//    for (int i = 0; i < 4; i++)

//    {

//    long l = (ulAddr & ulMask[i]) >> (i * 8);

//    ltoa(l, szAddr + strlen(szAddr), 10);

//    if (i != 3)

//    strcat(szAddr, ".");

//    }

//    return szAddr;

//    }

    sprintf( strTemp,"%d.%d.%d.%d",

        (nValue&0xff000000)>>24,

        (nValue&0x00ff0000)>>16,

        (nValue&0x0000ff00)>>8,

        (nValue&0x000000ff) );

    std::cout<<strTemp<<endl;

    return strTemp;

    }

int main ()

{

char str[] ="244.255.213.123";

const char * split = ".";

char * p;

int i =0;

int a[4];

int sum = 0x0;

p = strtok (str,split);

while(p!=NULL) {

//printf ("%s\n",p);

a[i] = atoi(p);

p = strtok(NULL,split);

//printf ("%x",a[i]);

i++;

}

sum = 256*256*256*a[0] + 256*256*a[1] + 256*a[2] +a[3];

printf ("%x",sum);

numbertoIp(sum);

getchar();

return 0;

}