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Specifying Alphameric Fields
40
program automatically adjusts the value of the exponent to indicate the actual
position of the decimal. The number of significant digits that will be printed can
be determined by the following rules:
if w
~
14, then 8 significant digits are printed
if w
<
14, then w-6 significant digits are printed
The following examples show how each of the quantities on the left is
printed according to the specification E10.3:
Value
In Storage
Printed
-.008
8000000602
-8.000E-03
.472
4720000000
b4.720E-01
.00000000006
6000000010
b6.000E-11
-10.0468
1004680002
-1.004E+01
1234567.8
1234567807
b1.234E+06
If your specification is not large enough, the program will automatically use the
specification E14.8.
In the examples just given, it can be seen that you must know the data in
order to specify a satisfactory format. Your specifications should provide for the
largest number of significant mantissa digits transmitted with the greatest ac-
curacy required.
Alphameric data can be read into the
FORTRAN
program from cards, paper tape,
or the typewriter. This data can be contained in the program and printed or
punched as part of the output data. Alphameric fields are often used to identify
totals or certain phases of the program. The following are typical output mes-
sages:
PROGRAM ERROR
OHMS, . . . . . . VOLTS
END OF PROGRAM
R C JONES
Alphameric fields require the
FORMAT
specification of wH, where w is the num-
ber of alphameric characters, including blanks, in the message.
The first message shown above could be typed by the following statements:
TYPE 9
9 FORMAT (14H PROGRAM ERROR)
(The count of 14 includes a blank position before and after "program.")
The next message in the example illustrates how totals can be identified in
the program. A print statement would be
PRINT 6,0, V
and the
FORMAT
statement might be,
6 FORMAT (lHO, F6.2, 5H OHMS, F6.2, 6H VOLTS)
The two preceding examples show ,how alphameric data is entered by a state-
ment in the source program. Alphameric data can also be read from individual
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