Luhn test of credit card numbers: Difference between revisions

=={{header|FutureBasic}}==

<syntaxhighlight lang="futurebasic">

include "NSLog.incl"

local fn LuhnCheck( cardStr as CFStringRef ) as BOOL

'~'1

NSInteger i, j, count, s1 = 0, s2 = 0

BOOL result = NO

// Build array of individual numbers in credit card string

NSUInteger strLength = len(cardStr)

CFMUtableArrayRef mutArr = fn MutableArrayWithCapacity(strLength)

for i = 0 to strLength - 1

CFStringRef tempStr = fn StringWithFormat( @"%C", fn StringCharacterAtIndex( cardStr, i ) )

MutableArrayInsertObjectAtIndex( mutArr, tempStr, i )

next

// Reverse the number array

CFArrayRef reversedArray = fn EnumeratorAllObjects( fn ArrayReverseObjectEnumerator( mutArr ) )

// Get number of array elements

count = len(reversedArray)

// Handle odd numbers

for i = 0 to count - 1 step 2

s1 = s1 + fn StringIntegerValue( reversedArray[i] )

next

// Hnadle even numbers

for i = 1 to count - 1 step 2

j = fn StringIntegerValue( reversedArray[i] )

j = j * 2

if j > 9 then j = j mod 10 + 1

s2 = s2 + j

next

if (s1 + s2) mod 10 = 0 then result = YES else result = NO

end fn = result

NSLogClear

if fn LuhnCheck( @"49927398716" ) == YES then NSLog (@"%@ is valid.", @"49927398716" ) else NSLog (@"%@ is not valid.", @"49927398716" )

if fn LuhnCheck( @"49927398717" ) == YES then NSLog (@"%@ is valid.", @"49927398717" ) else NSLog (@"%@ is not valid.", @"49927398717" )

if fn LuhnCheck( @"1234567812345678" ) == YES then NSLog (@"%@ is valid.", @"1234567812345678" ) else NSLog (@"%@ is not valid.", @"1234567812345678" )

if fn LuhnCheck( @"1234567812345670" ) == YES then NSLog (@"%@ is valid.", @"1234567812345670" ) else NSLog (@"%@ is not valid.", @"1234567812345670" )

HandleEvents

</syntaxhighlight>

{{output}}

<pre>

49927398716 is valid.

49927398717 is not valid.

1234567812345678 is not valid.

1234567812345670 is valid.

</pre>