Memory allocation problem Post: 302913411

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Top Forums UNIX for Dummies Questions & Answers Memory allocation problem Post 302913411 by bakunin on Saturday 16th of August 2014 10:11:10 AM

08-16-2014

Registered User

Quote:

Originally Posted by Abhishek_kumar

Can anyone guide me whats the problem ? although new codes are welcome, but i want to know problem with my code

Fair enough. The first problem, without even looking at what your code does, is obvious: use speaking names for your variables. Instead of juggling around "i", "j", "k", "p" and whatnot, like in good old FORTRAN/77, you should write names which tell you instantly what is in them: numbers, primes, factors, whatever. Not only will that help you with housekeeping, it will help you to concentrate on coding instead of remembering what "i" exactly means now in this function.

My personal favorite in this regard (but that is a matter of taste) is "Hungarian Style Notation" - or at least some personal subset variation of it. I prefix my variables names with a type indicator, which helps remembering this vital fact.

Secondly, regarding your code: the problem you are experiencing is IMHO in the function next_prime(), in this line:

Code:

	for(i=p+1;i<10000;i++)

Actually the program does what you told it to do and therefore this loop is interrupted at 9999 (not "9989 (or so )", as you said).

Aside from that your code inefficient to the extreme. Because "2" is a prime you could skip all even numbers and increment i by 2 instead of one, yes? This, btw., could be done with all the other found primes too. This consideration is the basis of the "Sieve of Eratosthenes", which will work for very small numbers like the ones you deal with. For bigger numbers you need better algorithms, like Lucas-Lehmer, Adleman-Pomerance-Rumely, etc..

For a quick introduction to primality tests and their pros and cons start with searching for "Primality Test" in Wikipedia.

I hope this helps.

bakunin

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locale::currency

Locale::Currency(3pm)					 Perl Programmers Reference Guide				     Locale::Currency(3pm)

NAME

       Locale::Currency - ISO three letter codes for currency identification (ISO 4217)

SYNOPSIS

	   use Locale::Currency;

	   $curr = code2currency('usd');     # $curr gets 'US Dollar'
	   $code = currency2code('Euro');    # $code gets 'eur'

	   @codes   = all_currency_codes();
	   @names   = all_currency_names();

DESCRIPTION

       The "Locale::Currency" module provides access to the ISO three-letter codes for identifying currencies and funds, as defined in ISO 4217.
       You can either access the codes via the "conversion routines" (described below), or with the two functions which return lists of all cur-
       rency codes or all currency names.

       There are two special codes defined by the standard which aren't understood by this module:

       XTS Specifically reserved for testing purposes.

       XXX For transactions where no currency is involved.

CONVERSION ROUTINES

       There are two conversion routines: "code2currency()" and "currency2code()".

       code2currency()
	   This function takes a three letter currency code and returns a string which contains the name of the currency identified. If the code
	   is not a valid currency code, as defined by ISO 4217, then "undef" will be returned.

	       $curr = code2currency($code);

       currency2code()
	   This function takes a currency name and returns the corresponding three letter currency code, if such exists.  If the argument could
	   not be identified as a currency name, then "undef" will be returned.

	       $code = currency2code('French Franc');

	   The case of the currency name is not important.  See the section "KNOWN BUGS AND LIMITATIONS" below.

QUERY ROUTINES

       There are two function which can be used to obtain a list of all currency codes, or all currency names:

       "all_currency_codes()"
	   Returns a list of all three-letter currency codes.  The codes are guaranteed to be all lower-case, and not in any particular order.

       "all_currency_names()"
	   Returns a list of all currency names for which there is a corresponding three-letter currency code. The names are capitalised, and not
	   returned in any particular order.

EXAMPLES

       The following example illustrates use of the "code2currency()" function.  The user is prompted for a currency code, and then told the cor-
       responding currency name:

	   $| = 1;    # turn off buffering

	   print "Enter currency code: ";
	   chop($code = <STDIN>);
	   $curr = code2currency($code);
	   if (defined $curr)
	   {
	       print "$code = $curr
";
	   }
	   else
	   {
	       print "'$code' is not a valid currency code!
";
	   }

KNOWN BUGS AND LIMITATIONS

       o   In the current implementation, all data is read in when the module is loaded, and then held in memory.  A lazy implementation would be
	   more memory friendly.

       o   This module also includes the special codes which are not for a currency, such as Gold, Platinum, etc.  This might cause a problem if
	   you're using this module to display a list of currencies.  Let Neil know if this does cause a problem, and we can do something about
	   it.

       o   ISO 4217 also defines a numeric code for each currency.  Currency codes are not currently supported by this module, in the same way
	   Locale::Country supports multiple codesets.

       o   There are three cases where there is more than one code for the same currency name.	Kwacha has two codes: mwk for Malawi, and zmk for
	   Zambia.  The Russian Ruble has two codes: rub and rur.  The Belarussian Ruble has two codes: byr and byb.  The currency2code() function
	   only returns one code, so you might not get back the code you expected.

SEE ALSO

       Locale::Country
	   ISO codes for identification of country (ISO 3166).

       Locale::Script
	   ISO codes for identification of written scripts (ISO 15924).

       ISO 4217:1995
	   Code for the representation of currencies and funds.

       http://www.bsi-global.com/iso4217currency
	   Official web page for the ISO 4217 maintenance agency.  This has the latest list of codes, in MS Word format. Boo.

AUTHOR

       Michael Hennecke <hennecke@rz.uni-karlsruhe.de> and Neil Bowers <neil@bowers.com>

COPYRIGHT

       Copyright (C) 2002, Neil Bowers.

       Copyright (c) 2001 Michael Hennecke and Canon Research Centre Europe (CRE).

       This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

perl v5.8.0							    2002-06-01						     Locale::Currency(3pm)