CS1001 Lecture 22

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CS1001 Lecture 22

• Formatted Input and Output

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Types of Input/Output

• List Directed
• PRINT , Temperature , Temperature
• READ , Choice
• User-Formatted
• PRINT (F8.2), Temperature
• PRINT 120, Temperature
• 120 FORMAT (F8.2)
• READ (I4, I6), Input1, Input2
• READ 130, Input1, Input2
• 130 FORMAT (I4, I6)

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PRINT Statement

• PRINT format-specifier, output-list
• format-specifier is
• , an asterisk (format is compiler-dependent)
• a character constant or variable
• the label of a FORMAT statement
• FORMAT statement can apply to more than one PRINT
  statement
• FORMAT statement should follow PRINT statement
  for readability
• output-list is an expression or list of
  expressions separated by commas

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Integer Output

• rIw or rIw.m (right justified)
• r - repetition indicator, indicating the number
  of fields
• I - denotes integer data
• w - number of spaces to display data
• m - minimum number of digits to display
• Example of 4I5.2
• 12345678900
• Example of 4I5
• 1234567890

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Real Output

• rFw.d (right justified)
• r - repetition indicator, indicating the number
  of fields (right-justified)
• F - denotes real (floating point) data
• w - total width of the field
• d - digits to right of decimal point
• Example of 2F8.3
• 123.4560.789

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Real, Exponential Notation

• rEw.d
• r - repetition indicator, indicating the number
  of fields
• E - real data, exponential notation,
• 0.0 lt mantissa lt 1.0
• w - total width of field
• d - digits to right of decimal point
• Example of 2E15.5
• 0.12345E08 0.23700E-01

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Character Output

• rA or rAw
• r - repetition indicator
• w - width (optional)
• Example
• X 12.3456
• Y -12.3456
• PRINT 264, X , X, Y , Y
• 264 FORMAT(1X, A, F6.2, A, F6.2)

X 12.35 Y -12.35

1X, A, F6.2, A, F6.2
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Positional Descriptors

• 1X at beginning of descriptor list denotes single
  line spacing AND single blank space
• nX elsewhere in descriptor list denotes number of
  blank spaces to be printed
• Tc tabs to the cth space on the line, so data
  begins there (absolute space number, but first
  space is blank)

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Control Characters

• 1X or (blank) for normal spacing
• 0 for double spacing
• 1 for advancing to a new page
• for overprinting current line
• Printer/system dependent, may not be in effect
• Slash Descriptor
• / causes output to begin on a new line
• /// would cause two blank lines to be inserted
  before data output

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Format Descriptors - Summary

• Iw or Iw.m for integer data
• A or Aw for character data
• x...x or x...x for character strings
• Fw.d for real data in decimal notation
• Ew.d real exponential notation
• Tc tab descriptors
• nX - inserts n blanks in an output line
• / - vertical spacing

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WRITE Statement

• WRITE (control-list) output-list
• control-list includes
• a unit specifier indicating the output device
• UNIT unit-specifier
• or simply unit-specifier
• a format-specifier
• FMT format-specifier
• or simply format-specifier
• output-list is same as for PRINT statement

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Unit Numbers

• Standard Input device is the terminal keyboard or
  UNIT 5
• Standard Output device is the terminal display
  monitor or UNIT 6
• Standard Error device is the terminal display
  monitor or UNIT 0

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Equivalent WRITE Statements

• All of which are equivalent
• PRINT , Time,Temp
• WRITE (6, ) Time, Temp
• WRITE (6, FMT ) Time, Temp
• WRITE (UNIT 6, FMT ) Time, Temp
• WRITE (NOUT, ) Time, Temp where NOUT 6
• WRITE (UNIT NOUT, FMT ) Time, Temp

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READ Statement

• READ format-specifier, input-list
• format-specifier is
• (an asterisk)
• a character variable or constant
• the label of a FORMAT statement
• use the first form for this class until we get
  into file handling
• input-list is a variable or list of variables

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General READ Statement

• READ (control-list) input-list
• input-list is same as for READ statement
• control-list includes
• a unit specifier indicating the output device
• UNIT unit-specifier
• or simply unit-specifier
• a format-specifier
• FMT format-specifier
• or simply format-specifier

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READ Statements

• All of which are equivalent
• READ , Time, Temp
• READ (5, ) Time, Temp
• READ (5, FMT ) Time, Temp
• READ (UNIT 5, FMT ) Time, Temp
• READ (NIN, ) Time, Temp where NIN 5
• READ (UNIT NIN, FMT ) Time, Temp

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Additional Format Material
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Format Descriptors 1/2

• Iw or Iw.m for integer data
• Bw or Bw.m for integer data in binary form
• Ow or Ow.m for integer data in octal form
• Zw or Zw.m for integer in hexadecimal
• A or Aw for character data
• x...x or x...x for character strings
• Lw for logical data

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Format Descriptors 2/2

• Fw.d for real data in decimal notation
• Ew.d or Ew.dEe real exponential notation
• 0.0 lt mantissa lt 1.0
• ESw.d or ESw.dEe real scientific notation
• 1.0 lt mantissa lt 10.0 (unless 0.0)
• ENw.d or ENw.dEd real engineering notat.
• 1.0 lt mantissa lt 1000.0, exponent multiple of 3
• Gw.d or Gw.dEe general i/o descriptor

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Descriptor Meanings

• w - positive integer constant - width
• m - nonnegative integer constant - minimum number
  of digits to be displayed
• d - nonnegative integer constant - digits to
  right of decimal point
• e - nonnegative integer constant - digits in
  exponent
• x - a character

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Other Integer Representation

• Given the integer value of 200 decimal
• Format B9 produces 11001000
• Format O4 produces 310
• Format Z3 produces C8

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Do Not Worry About

• S, SP and SS optional output plus sign controls
• SP specifies that optional plus signs are to be
  printed
• SS suppresses optional plus signs
• S restores the processor option
• BN and BZ blank character controls
• BN treats blanks as nulls, and ignores them
• BZ treats blanks as zeros
• kP scale factor control (2P treats input of 123
  as 1.23 internally

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Other Format Descriptors

• General descriptor Gw.d and Gw.dEe are the same
  as Iw format, values of d and e are ignored.
• Relative tab descriptors TRw and TLw
• TRw tabs right w positions and is identical in
  operation to wX
• TLw tabs left w positions and is a form of
  backward tabbing, which is to be avoided
• There is no reason to use any of these

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Real, Scientific Notation

• rESw.d or rESw.dEe
• r - repetition indicator, indicating the number
  of fields
• ES - real data, scientific notation
• w - total width of field
• d - digits to right of decimal point
• e - number of positions to display exponent
• Example of 2ES15.5
• 1.23450E082.37000E-01

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Real, Engineering Notation

• rENw.d or rENw.dEe
• r - repetition indicator, indicating the number
  of fields
• EN - real data, engineering notation
• w - total width of field
• d - digits to right of decimal point
• e - number of positions to display exponent
• Example of 2EN15.5
• 123.45000E06237.00000E-03

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Special Descriptors

• Tc, TLn, TRn - tab descriptors
• c - positive integer constant representing
  character position
• n - positive integer constant specifying number
  of character positions
• nX - inserts n blanks in an output line
• / - vertical spacing