#include<stdio.h>

int stoipa(char *s)
{
   int ipa, i;
   int A[4]; 
   char B[4];

   sscanf(s,"%d.%d.%d.%d",A,A+1,A+2,A+3);
   for(i=0;i<4;i++) B[i] = (char) A[i];
   
   ipa = *((int *) B);
   return ipa;
}

char * ipatos(int ipa)
{  char * A;
   A = (char *) malloc(16);   // allocate 16 bytes
   sprintf(A,"%d.%d.%d.%d",*((unsigned char *)(&ipa)), 
     *(((unsigned char *)(&ipa)) + 1),
     *(((unsigned char *)(&ipa)) + 2),
     *(((unsigned char *)(&ipa)) + 3));
   return A;
}

int main(int argc, char* argv[])
{  int ip;
   ip = stoipa(argv[1]);   
   printf("4-byte ip == %d\n",ip);
   printf("original string : %s\n",ipatos(ip));
   exit(0);
}