Sample MATLAB session for characters
+ Each character has a numerical code
+ Extended ASCII goes from 0 to 255
+ use $char$ to convert integer to character
+ use $double$ to convert character to integer
-------------------------------------------------------------------------------
All ASCII characters:
>> char(0:255)

ans =

123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|
}~ ¡¢£¤¥¦§¨©ª«¬­®¯°±²³´µ¶·¸¹½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëì
íîïðñòóôõö÷øùúûüýþÿ
-------------------------------------------------------------------------------
Keyboard characters:
>> char(33:126)

ans =

!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`
abcdefghijklmnopqrstuvwxyz{|}~
-------------------------------------------------------------------------------
Digits:
>> char(48:57) 

ans =

0123456789
-------------------------------------------------------------------------------
Punctuation:
>> [char(33:47),char(91:96),char(123:126)]

ans =

!"#$%&'()*+,-./[\]^_`{|}~
-------------------------------------------------------------------------------
Uppercase letters:
>> char(65:90)

ans =

ABCDEFGHIJKLMNOPQRSTUVWXYZ
-------------------------------------------------------------------------------
Lowercase letters:
>> char(97:122)

ans =

abcdefghijklmnopqrstuvwxyz
-------------------------------------------------------------------------------
Bizarro Characters:
>> char(123:255)

ans =

¡¢£¤¥¦§¨©ª«¬­®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞß
àáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ
-------------------------------------------------------------------------------
Waiting for Unicode:
>> char(256:65355)
no output
-------------------------------------------------------------------------------