Check
Writer – how to manipulate strings in Matlab

This
Matlab program is a ‘check
writer’. You must provide a numerical date, payee of
the check, and amount
to be written (any number between 1.00 and 999,999.99
dollars).
The program translates
the date and amount to
words, and prints
providing some spacing within the check (easily modifiable).
We achieve this task using simple string concatenation in Matlab. 
You
should regard the listing as a sample
of a checkwriting code. The algorithm
for translating numbers
into words (or working with strings) is general and may
be easily adapted to other programming languages.
There
are five sections to convert numbers into words in this Matlab program.
 Processing
the thousands
 Processing
the hundreds
 Processing
the tens
 Processing
cents
 Main
code that accesses and controls the other four sections
We use
cell arrays
to handle the necessary strings, and the process consists in
finding the correct index
of an initial given ‘dictionary’.
The
Matlab function to work with the first three digits (thousands) is as
follows.
The string (named ‘words’) is updated after each digit is evaluated.
function [words,
h, u] = thousands(amount)
global number
words =
[];
%
Find if there are thousands
t =
floor(amount/1000);
if (t ==
0)
h
= 0;
u
= 0;
return
end
%
Find the hundreds
h =
floor(amount/100000);
if h >
0
words
= [number{h} '
HUNDRED'];
end
%
Find the last two digits
u =
floor(amount/1000)  h*100;
if (0 <
u) & (u < 21)
words
= [words '
'
number{u}];
else
words = [words tens(u, [])];
end
%
End string with word 'thousand'
words
=
[words '
THOUSAND'];
The 'check writer'
function to work with the three digits previous to the
decimal
point (hundreds) is as follows. Again, the string (named ‘words’) is
updated
after each digit is evaluated and the Matlab algorithm flows in a
similar way
than before.
function words =
hundreds(amount, words, h, u)
global number
%
Find if there are hundreds
hu =
floor(amount  h*1e5  u*1e3);
if (hu ==
0)
words
= [words];
return
end
%
Find the hundreds
h =
floor(hu/100);
if h >
0
words
= [words '
'
number{h} '
HUNDRED'];
end
%
Find the last two digits
u = hu 
h*100;
if (0 <
u) & (u < 21)
words
= [words '
'
number{u}];
else
words = [words tens(u, [])];
end
The section to translate the last two digits of
each
group of three elements is given below. Note that the index to locate the
correct number in the given dictionary (defined in the control section,
below)
works only for numbers beyond
the first 20 elements in the list, due to the way
that English syntax works. For the first 20 elements, it 's
not necessary to go through this script.
function words =
tens(u, words)
global number
%
Work with the last two digits of the group of three
if u == 0
words
= [words];
return
end
%
Find the correct index of the appropriate multiple of 10
words =
[words '
' number{floor((u
 20)/10 + 20)}];
units =
u  floor(u/10)*10;
if units
== 0
return
end
%
Add a dash and the appropriate number if there are units
words =
[words '' number{units}];
Now, this is the function
to add the remaining cents to the almost ready final string. It
converts
numbers into strings using command 'num2str'.
function words =
cents(amount, words)
c =
amount*100  floor(amount)*100;
if c <
10
cents
= ['0' num2str(c)];
else
cents = num2str(c);
end
words =
[words '
AND ' cents '/100'];
The control module that accesses the previous four
routines for our check writer is as follows (name it check_writer.m, so
you can run it from the command window):
clc;
clear
global number
month =
{'January', 'February', 'March', 'April', 'May',...
'June', 'July', 'August','September', 'October',...
'November', 'December'};
number =
{'ONE', 'TWO', 'THREE', 'FOUR', 'FIVE',...
'SIX', 'SEVEN', 'EIGHT', 'NINE', 'TEN',...
'ELEVEN', 'TWELVE', 'THIRTEEN', 'FOURTEEN', 'FIFTEEN',...
'SIXTEEN', 'SEVENTEEN', 'EIGHTEEN', 'NINETEEN',...
'TWENTY', 'THIRTY', 'FORTY', 'FIFTY',...
'SIXTY', 'SEVENTY', 'EIGHTY', 'NINETY'};
disp('Check
Writer ')
disp('
')
dat =
input('Enter
date (MMDDYY): ',
's');
m =
str2num(dat(1:2));
name =
input('Name
of payee: ', 's');
a =
input('Amount
of check (include two decimals): ', 's');
amount =
str2num(a);
if (amount
< 1)(amount > 999999.99)
disp('Sorry, amount is out of
range...')
return
end
x =
input('Prepare
printer (enter when ready)... ', 's');
disp('
')
dat_str
= ['
'...
month{m} ' '
dat(3:4) ',
' '20' dat(5:6)];
disp(dat_str)
amount_str
= ['
'...
'$' a];
disp(amount_str)
name_str
= ['
'
name];
disp(name_str)
[words,
h, u] = thousands(amount);
words =
[hundreds(amount, words, h, u)];
words =
[cents(amount, words) '
DOLLARS'];
disp(words)
Now, let’s try our code, let's change numbers into words for a good application:
Check
Writer 
Enter
date (MMDDYY): 122309
Name of payee: Heavenly Bank of Algorithmland
Amount of check (include two decimals): 23999.00
Prepare
printer (enter when ready)...
December 23, 2009
$23999.00
Heavenly
Bank of Algorithmland
TWENTYTHREE
THOUSAND NINE HUNDRED NINETYNINE AND 00/100 DOLLARS
Another run:
Check
Writer 
Enter
date (MMDDYY): 010110
Name of payee: poohprod.ru
Amount of check (include two decimals): 734100.15
Prepare
printer (enter when ready)...
January 01, 2010
$734100.15
poohprod.ru
SEVEN
HUNDRED THIRTYFOUR THOUSAND ONE HUNDRED AND
15/100 DOLLARS
From 'Check Writer' to home
From
'Check Writer' to 'Matlab Programming'
