dev-cpp-users

[Dev-C++] palindrome base prgm

[chromatonus 7. <chr...@ho...>]

hi, I am writing a prgm that takes a number (like 19), and its base, (10 in 
this case), and perform the following operation until a palindrome is 
obtained:

add the reverse of 19
19+91 = 110
add the reverse of 110
110 + 11 = 121....a palindrome,
and the prgm should print out the 121.

I think there are several caveats:
bases can range from 10 to 16, so the A,B,C,D,E,F is tricky to handle as 
numbers, because the input would be like A32 for example.
And how to reverse the number and check to see if it's a palindrome, and 
also doing addition in different bases. Any tip on these will be greatly 
appreciated!


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RE: [Dev-C++] palindrome base prgm

[Ioannis V. <no...@ya...>]

> -----Original Message-----
> From: dev...@li...=20
> [mailto:dev...@li...] On Behalf=20
> Of chromatonus 712
> Sent: Saturday, March 09, 2002 4:10 AM
> To: dev...@li...
> Subject: [Dev-C++] palindrome base prgm
>=20
>=20
>=20
> hi, I am writing a prgm that takes a number (like 19), and=20
> its base, (10 in=20
> this case), and perform the following operation until a palindrome is=20
> obtained:
>=20
> add the reverse of 19
> 19+91 =3D 110
> add the reverse of 110
> 110 + 11 =3D 121....a palindrome,
> and the prgm should print out the 121.
>=20
> I think there are several caveats:
> bases can range from 10 to 16, so the A,B,C,D,E,F is tricky=20
> to handle as=20
> numbers, because the input would be like A32 for example.
> And how to reverse the number and check to see if it's a=20
> palindrome, and=20
> also doing addition in different bases. Any tip on these will=20
> be greatly=20
> appreciated!

Get the number as a string, check it and reverse it and then convert it
to number. I am still studying C++ so i do not know if it provides some
else string to number facility, i so for the conversion i should suggest
sscanf() on string::c_str().



Ioannis
=20
* Ioannis Vranos
* Programming pages: http://www.noicys.d2g.com
* Alternative URL: http://run.to/noicys

Re: [Dev-C++] palindrome base prgm

[Jason H. <jas...@bt...>]

A quick note. The C++ equivalent of sscanf and sprintf is the 'stringstream'
class and it's related classes (istringstream, and  ostringstream). Note
that 'stringstream' is the current standard name, but previously it was
known as 'strstream'. Once you have created the buffer you can operate on it
in much the same way as with cout and cin (using << and >>). It's header is
<sstream> (I think?).

Jason.


----- Original Message -----
From: "Ioannis Vranos" <no...@ya...>
To: "Dev-C++" <dev...@li...>
Sent: Saturday, March 09, 2002 3:31 PM
Subject: RE: [Dev-C++] palindrome base prgm

I am still studying C++ so i do not know if it provides some
else string to number facility, i so for the conversion i should suggest
sscanf() on string::c_str().

Ioannis

* Ioannis Vranos
* Programming pages: http://www.noicys.d2g.com
* Alternative URL: http://run.to/noicys


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Re: [Dev-C++] palindrome base prgm

[Jason H. <jas...@bt...>]

You can choose to manipulate the values as strings, reversing the string and
converting it to an integer to perform the addtion. You may need to write
your own conversion function as I'm not sure if C/C++ has a standard one for
differing bases (radix). You can then convert back to a string (in the same
base) and perform the manipulation again until you get something like normal
== reverse?

Another way is to make an array with an integer for each digit. That way you
can can just calculate the exponent for each possition according to it's
base, doing it forward and backward, and then break the result back down
into individual digits. i.e.

19 = 1 * 10^2 + 9 * 10^1
91 = 9 * 10^2 + 1 * 10^1

and

110 / 10^0 % 10 = 0
110 / 10^1 % 10 = 1
110 / 10^2 % 10 = 1

which are the individual digits of 110 etc...

It seems more complicated, but may be easier than writing your own
conversion from string to base 12 (or whatever) and back. I may do more work
later.

Jason.

PS: You may want to check my math as I just did it quickly, and it could be
done better.
PPS: '^' represents  'raised to the power of', but doesn't exist in C/C++,
and % is the modulus operator.

----- Original Message -----
From: "chromatonus 712" <chr...@ho...>
To: <dev...@li...>
Sent: Saturday, March 09, 2002 2:10 AM
Subject: [Dev-C++] palindrome base prgm


>
> hi, I am writing a prgm that takes a number (like 19), and its base, (10
in
> this case), and perform the following operation until a palindrome is
> obtained:
>
> add the reverse of 19
> 19+91 = 110
> add the reverse of 110
> 110 + 11 = 121....a palindrome,
> and the prgm should print out the 121.
>
> I think there are several caveats:
> bases can range from 10 to 16, so the A,B,C,D,E,F is tricky to handle as
> numbers, because the input would be like A32 for example.
> And how to reverse the number and check to see if it's a palindrome, and
> also doing addition in different bases. Any tip on these will be greatly
> appreciated!
>
>
> _________________________________________________________________
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http://explorer.msn.com/intl.asp.
>
>
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