CHARACTER type

• Y/N answer to a question
• menu selection
• etc

Character Sets

binary codes <=> character values

• ASCII (standard)
• EBCDIC (IBM)
• ISO 646 (ASCII + national characters)
• ISO 8859/1 (European languages)

arbitrary, BUT:

• digits contiguous
• lower case letters contiguous
• upper case letters contiguous

CHARACTER values

write in apostrophes:

'A'
'8'
'?'
' '
'''
'"'

NB avoid confusion: the CHARACTER '1' is not the same as INTEGER 1, or FLOAT 1.0

Attributes

Attributes of the data type as a whole:

• CHARACTER'FIRST first in character set
• CHARACTER'LAST last in character set

Attributes of individual CHARACTER values:

• CHARACTER'PRED(char)
  • PREDecessor
  • example: CHARACTER'PRED('N') = 'M'
• CHARACTER'SUCC(char)
  • SUCCessor
  • example: CHARACTER'SUCC('N') = 'O'
• CHARACTER'POS(char)
  • ASCII code
  • example: CHARACTER'POS('A') = 65
• CHARACTER'VAL(int)
  • character for given code
  • example: CHARACTER'VAL(66) = 'B'

CHARACTER operations

Input/Output

• TEXT_IO
• GET
  • blanks skipped; ' ' to enter a blank
• PUT

Comparison

• Relational operators compare code values

Other

• character value attributes