1. 21 April, 2000 CS1001 Lecture 22 Formatted Input and Output

2. 21 April, 2000 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)

3. 21 April, 2000 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

4. 21 April, 2000 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: ^1234^^567^^^89^^^00 Example of 4I5: ^1234^^567^^^89^^^^0 5555 5555

5. 21 April, 2000 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: ^123.456^^^0.789 8833

6. 21 April, 2000 Real, Exponential Notation rEw.d –r - repetition indicator, indicating the number of fields –E - real data, exponential notation, 0.0 <= mantissa < 1.0 –w - total width of field –d - digits to right of decimal point Example of 2E15.5: ^^^^0.12345E+08 ^^^^0.23700E-01 155 5

7. 21 April, 2000 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) 1X, A, F6.2, A, F6.2 X = 12.35 Y = -12.35 ^ ^ ^^ ^ ^ ^

8. 21 April, 2000 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)

9. 21 April, 2000 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

10. 21 April, 2000 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

11. 21 April, 2000 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

12. 21 April, 2000 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

13. 21 April, 2000 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

14. 21 April, 2000 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

15. 21 April, 2000 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

16. 21 April, 2000 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

17. 21 April, 2000 Additional Format Material

18. 21 April, 2000 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

19. 21 April, 2000 Format Descriptors 2/2 Fw.d for real data in decimal notation Ew.d or Ew.dEe real exponential notation 0.0 <= mantissa < 1.0 ESw.d or ESw.dEe real scientific notation 1.0 <= mantissa < 10.0 (unless = 0.0) ENw.d or ENw.dEd real engineering notat. 1.0 <= mantissa < 1000.0, exponent multiple of 3 Gw.d or Gw.dEe general i/o descriptor

20. 21 April, 2000 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

21. 21 April, 2000 Other Integer Representation Given the integer value of “200” decimal Format B9 produces “^11001000” Format O4 produces “^310” Format Z3 produces “^C8”

22. 21 April, 2000 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

23. 21 April, 2000 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

24. 21 April, 2000 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: ^^^^1.23450E+08^^^^2.37000E-01

25. 21 April, 2000 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: ^^123.45000E+06^^237.00000E-03

26. 21 April, 2000 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