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jB wrote:
> Could anyone please help me with a couple of small routines to convert a
> base10 number into a base32 string and a routine to convert base32 string
> into a base10 number.
>
> A class would be great.

If you're using the VCL:

String Str = IntToHex( 123456, 2 ); // 2nd parameter is pad to how many 
characters.

int i = StrToInt( "0x10" );

HTH

Jon

"jB" <jb@britesc.com> wrote in message 
news:47c53b22@newsgroups.borland.com...

> Could anyone please help me with a couple of small routines to convert a
> base10 number into a base32 string and a routine to convert base32 string
> into a base10 number.

You didn't answer Jason's speculation (in language.cpp) that this is 
homework.  If it is homework then you would learn more by doing it yourself 
(and you should use the .students newsgroup).

Either way there are *plenty* of examples already out there.  You just need 
to use a search engine.  If you want to search previous newsgroup postings 
then use http://groups.google.com and search for something like "base32 
base10 conversion".

The core of the algorithm is that you will take your number and continually 
divide it by 32 (taking the remainder as your string characters) until you 
are left with 0.  When converting the other way you will do the opposite, 
multiply your number by 32 and add the character from the string until the 
string is empty.  The characters in the string will use an alphabet of your 
choosing.  There are several "standards".  To see a good write-up on this go 
to http://en.wikipedia.org/wiki/Base32

Clayton 

"Jonathan Benedicto" <invalid@nobody.com> wrote in message 
news:47c58914$1@newsgroups.borland.com...

> String Str = IntToHex( 123456, 2 ); // 2nd parameter is pad to how many 
> characters.
>
> int i = StrToInt( "0x10" );

The OP wants a Base32 algorithm not Base16

Clayton

"Clayton Arends" <nospam_claytonarends@hotmail.com> wrote:

>> int i = StrToInt( "0x10" );
>
>The OP wants a Base32 algorithm not Base16

So do it twice!

Alan Bellingham
-- 
Team Browns
ACCU Conference 2008: 2-5 April 2008 - Oxford, UK

Clayton Arends wrote:
> The OP wants a Base32 algorithm not Base16

Doh! Thanks.

Jon 

jB wrote:
> 
> Could anyone please help me with a couple of small routines to convert a
> base10 number into a base32 string and a routine to convert base32 string
> into a base10 number.
> 

The C standard library has the strtol() function which will convert a 
string to a long using a base between 2 and 36. There is no standard 
function to do the complementary conversion, at least that I am aware of.

I have written a small function to do that long to string conversion 
using a base between 2 and 36. It is copied below. There is also a small 
command line test program that converts its first argument using the 
second argument as a base.

These functions should let you do your conversions to and from base 32.

HTH
Dennis Cote



#include <stdlib.h>
#include <stdio.h>

static char digit_symbols[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVXYZ";

bool ltostr(long n, char* str, int base)
{
     char buf[33];
     char* p = buf;

     if (!str || base < 2 || base > 36)
         return false;

     if (n < 0) {
         *str++ = '-';
         n = -n;
     }

     do {
         *p++ = digit_symbols[n % base];
         n /= base;
     } while (n > 0);

     do {
         *str++ = *(--p);
     } while (p > buf);

     *str = 0;
     return true;
}


#pragma argsused
int main(int argc, char* argv[])
{
     char str[33];
     long m;
     long n = atol(argv[1]);
     int base = atoi(argv[2]);

     printf("n = %ld base 10\n", n);

     if (ltostr(n, str, base))
         printf("n = %s base %d\n", str, base);
     else
         printf("error converting n\n");

     m = strtol(str, NULL, base);

     printf("m = %ld base 10\n", m);

     return 0;
}