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Convert Integers to Their Textual Description

, 6 May 2014 Apache
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Convert an integer to its textual description

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Preface

Ever wanted a friendlier way to display any given amount to a user? Or, perhaps you're coding a grammatically correct English application, racing game, tracking visitors, or creating an accounting solution. Whatever the case, there are some times when a programmer needs to represent a number as a written word (i.e., 4 becomes "four"). And, that's the goal of this routine.

The original version (as most typical implementations of this) used strings for calculations and conversions and while it worked, it was slower. However, I updated the algorithm to not do this anymore. As a result, I noticed an average 310% speed increase (on a Pentium IV) despite the fact I also added support for much larger numbers as well.

Usage

Using this routine is straightforward. It does make use of C-style strings as they are fast and extremely portable with most environments. The sole routine that does the grunt work is named GetNumWord() and is prototyped as follows...

// prototype/signature
char *GetNumWord (long long llNumber, char *szDest, 
                  unsigned int unLen, bool bOrdinal, bool bUseAnd);

Parameter Descriptions:

llNumber = This is the 64-bit number to convert.
szDest = Pointer to the output buffer (char array).
unLen = Size in bytes of the output buffer (not string length).
bOrdinal = Setting this to true will return the ordinal version of the number (e.g., first); otherwise, the cardinal version is returned (e.g., one).
bUseAnd = This will determine if the and conjunction is used in the output or not (e.g., One Hundred And One).

Example

char szBuffer[100] = {0};
GetNumWord(5001, szBuffer, sizeof(szBuffer), false, false);
GetNumWord(-10, szBuffer, sizeof(szBuffer), false, false);
GetNumWord(123, szBuffer, sizeof(szBuffer), true, true);

Will return...

"Five Thousand One"
"Negative Ten"
"One Hundred And Twenty-Third"

Limitations

The function takes a long long as the number parameter. On most 32-bit and 64-bit systems, this means the lowest number you can pass is -9,223,372,036,854,775,808 and the highest number is 9,223,372,036,854,775,807.

Also, 64-bit arithmetic on a 32-bit CPU is a bit slower. However, the difference is negligible for most applications, and 64-bit CPUs are becoming more and more mainstream, so this consideration will soon be obsolete.

Credits & History

Article's Author - Jeremy Falcon
The "and" Conjunction Suggestion - benjymous
Memory Leak Tip - James Curran
  • 2007-01-13 - Ver. 2.0 released.
  • 2002-04-12 - Ver. 1.1 released.
  • 2002-04-01 - Ver. 1.0 released.

License

Permission is granted to anyone to use this software for any purpose on any computer system, and to alter it and redistribute it freely, subject to the following restrictions found in NumWord.c. It's nothing big. Essentially, it states that if your computer blows up then it's not my fault, and if you use this code then give credit where it's due.

License

This article, along with any associated source code and files, is licensed under The Apache License, Version 2.0

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About the Author

Jeremy Falcon
Software Developer (Senior)
United States United States
I've been in software development since 1994. Over the years I've learned quite a lot in what it takes to complete the process of pushing out a quality product to customers in a timely fashion. As most of my colleagues could attest, there have been many challenges in our new and growing field in the past couple of decades as the industry matures rapidly. Much more so than most others historically speaking.
 
As such, I've learned one of the best aspects of software engineering is embracing the change that inherently comes along with it as new technologies constantly emerge to help us improve our world one application at a time as we make sense of the overwhelming amount of data now prevalent in the Information Age.
 
We truly live in a time unlike that ever known to mankind in recorded history, and it is my hope to do my part to help it along to face the challenges and demands of tomorrow.

Comments and Discussions

 
GeneralRe: Can we have the PHP? PinmemberChinaHorse21-Mar-04 1:28 
GeneralRe: Can we have the PHP? PinmemberJeremy Falcon21-Mar-04 4:25 
GeneralYes, SSH PinmemberChinaHorse21-Mar-04 23:17 
GeneralRe: Yes, SSH PinmemberJeremy Falcon23-Jun-04 9:07 
GeneralIdeas Ideas! PinmemberNguyen Binh3-Apr-03 23:19 
GeneralRe: Ideas Ideas! PinmemberJeremy Falcon23-Jun-04 9:17 
GeneralRe: Ideas Ideas! PinmemberMember 761463224-Nov-13 2:18 
GeneralBuffer overwrite waiting to happen. PinmemberAnonymous2-Jul-02 12:10 
Here's your prototype:
 
char *getNumCardinal (char *szDest, unsigned long num, short isProper, short isAnd);
 
You indicate szDest needs to be passed in, fine... However, consider the following code:
 
char buffer[3];
getNumCardinal (buffer,12,TRUE,TRUE);
 
That just caused a buffer overwrite, because you wrote "twelve\0" into my 3-byte buffer.   That's no good.   Not at all.   You need to either use a string class (which manages it's own internal buffer), or have the caller pass in the length of the string he has allocated.
 
Look up some references on the usage of strcpy vs. strncpy.   It's essentially the same problem, and I can't believe noone here pointed it out...
 

GeneralRe: Buffer overwrite waiting to happen. PinmemberJeremy Falcon2-Jul-02 15:11 
GeneralTwo Notes.... PinmemberJames Curran8-Apr-02 4:02 
GeneralRe: Two Notes.... PinmemberJeremy Falcon8-Apr-02 5:16 
GeneralRe: Two Notes.... PinadminChris Maunder9-Apr-02 15:35 
GeneralRe: Two Notes.... PinmemberJeremy Falcon9-Apr-02 16:24 
GeneralOvercome limitation of interger to text string PinmemberNguyen Luong Son2-Apr-02 18:35 
GeneralRe: Overcome limitation of interger to text string PinmemberJeremy Falcon3-Apr-02 5:29 
GeneralRe: Overcome limitation of interger to text string PinmemberMember 761463224-Nov-13 2:15 
GeneralFYI PinmemberJeremy Falcon2-Apr-02 16:16 
Questionhow about a redneck version? PinmemberChris Losinger2-Apr-02 8:09 
AnswerRe: how about a redneck version? PinmemberJeremy Falcon2-Apr-02 10:45 
GeneralExtra addition for English users Pinmemberbenjymous2-Apr-02 4:07 
GeneralRe: Extra addition for English users PinmemberJeremy Falcon2-Apr-02 4:15 
GeneralRe: Extra addition for English users PinmemberTim Smith2-Apr-02 15:56 
GeneralRe: Extra addition for English users PinmemberJeremy Falcon2-Apr-02 16:14 
GeneralRe: Extra addition for English users Pinmemberbenjymous2-Apr-02 22:53 
GeneralNot So Unique PinmemberDave Goodman1-Apr-02 21:47 

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