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In this video, we'll talk
about the functions that

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we can use with characters.

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This cctype library includes very
simple and very useful functions

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that allow the testing of characters
for various properties as well as

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the conversion of characters from
upper to lower or lower to uppercase.

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In order to use these functions,
you must include cctype.

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The functions all expect
a single character.

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In the case of the testing functions,
they evaluate to true or false.

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And the conversion functions
return the converted character.

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Let's see some of these functions.

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This table contains some of
the functions in cctype that

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allow for testing of characters.

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You call the function and
pass into character you wish

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to test in the parentheses.

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The function that evaluates
to true or false depending on

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whether the character has the
property your testing or not.

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Isalpha test to see if a character
is a letter, either uppercase or

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lowercase and evaluates to true
if it is or false otherwise.

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Isalnum test to see if the
character is a letter or digit.

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Isdigit test to see if
the character is a digit.

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Islower test to see if the
character is a lowercase letter.

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Isprint test to see if the
character is a printable character.

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Ispunct test to see if the
characters of punctuation character.

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Isupper test to see if the
characters and uppercase letter.

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And isspace test to see if the
characters of whitespace character.

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There are a few other
functions in cctype that I

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haven't listed in the table.

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You can refer to the
c++ docs for those.

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Now let's see the
conversion functions.

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The two character conversion
functions are tolower and toupper.

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Tolower evaluates the lower case
equivalent of the character passed in

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and toupper the uppercase equivalent.

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If these functions can't
perform the conversion, then a

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function simply evaluate to the
character that was passed in.

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As you can see, these
functions are very handy.

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They're also extremely efficient.

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We'll use these functions
in the next few videos when

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we talk more about strings.

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In the next video, we'll
learn about c style strings.

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I'll see you there.