converting to 32 bit long form

arvind_khadri's Avatar, Join Date: Sep 2007
Go4Expert Member
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....
0
Salem's Avatar, Join Date: Nov 2007
Ambitious contributor
Do you have any examples of what you're trying to accomplish?
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arvind_khadri's Avatar, Join Date: Sep 2007
Go4Expert Member
if i enter 153.18.8.105 the o/p should be 2568095849....for separation u can use strtok for separating.....
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Salem's Avatar, Join Date: Nov 2007
Ambitious contributor
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.
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arvind_khadri's Avatar, Join Date: Sep 2007
Go4Expert Member
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.....
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Salem's Avatar, Join Date: Nov 2007
Ambitious contributor
You mean that
2568095849 is (153 << 24) + (18 << 16) + (8 << 8) + 105

It's just a loop, with a shift and and add.
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arvind_khadri's Avatar, Join Date: Sep 2007
Go4Expert Member
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...
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arvind_khadri's Avatar, Join Date: Sep 2007
Go4Expert Member
i wasnt able to sihft it...whenver i giver 153<<24 it shows 0 as o/p....
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Salem's Avatar, Join Date: Nov 2007
Ambitious contributor
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.
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arvind_khadri's Avatar, Join Date: Sep 2007
Go4Expert Member
i could get the following code...but cant understand how it works.....can u pls explain it....
code:cpp

Code:
#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();
}

Last edited by shabbir; 18Nov2007 at 21:07.. Reason: Code block