[arvind_khadri]

hi...hey guys i just wanted a help on this....how do i convert a given number to a 32 bit long form...plz help....

[Salem]

Do you have any examples of what you're trying to accomplish?

[arvind_khadri]

if i enter 153.18.8.105 the o/p should be 2568095849....for separation u can use strtok for separating.....

[Salem]

Use strtol().
One of the things it returns is a pointer to where it got to (ie, the dots between numbers).
This you use to locate the start of the next number.

[arvind_khadri]

well salem i got tat part...but the next thing is how do i convert...tats wat am nt able to get...so i needed help on it.....

[Salem]

You mean that
2568095849 is (153 << 24) + (18 << 16) + (8 << 8) + 105

It's just a loop, with a shift and and add.

[arvind_khadri]

thanks for tat...well so rt nw u mean to say tat find the binary eqvt and keep shifting and then concatenate the thing to find final result??if u could post the code here it would be really very helpful of u...

[arvind_khadri]

i wasnt able to sihft it...whenver i giver 153<<24 it shows 0 as o/p....

[Salem]

Well it would do, if you were storing the result in an unsigned char say. All the bits fell off the end!

It needs to be in an unsigned long before you shift it left 24 bits.

[arvind_khadri]

i could get the following code...but cant understand how it works.....can u pls explain it....
code:cpp

#include<string.h>
#include<conio.h>
#include<stdio.h>
#include<math.h>
union ipadd
 {
 unsigned long int a;
 } e;
void main()
{
char ip[100];
char *p;
int i,n,j,po;
unsigned long int d;
e.a=0;
clrscr();
printf("\nenter the ip");
scanf("%s",ip);
p=strtok(ip,".");
n=strlen(p) ;
d=0;
po=0;
for(i=n-1;i>=0;i--)
 {
 d=d+(*(p+i)-48)*pow(10,po);
 po++;
 }
e.a=d*pow(256,3);
for(j=2;j>=0;j--)
 {
  p=strtok(NULL,".");
  n=strlen(p);
  d=0;
  po=0;
  for(i=n-1;i>=0;i--)
    {
     d=d+(*(p+i)-48)*pow(10,po);
     po++;
    }
  e.a=e.a+d*pow(256,j);
  }
printf("\n the ip add is :%lu",e.a);
getch();
}