Selective file copy: Difference between revisions
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Show how file processing as known from PL/I or COBOL can be implemented in the |
Show how file processing as known from PL/I or COBOL can be implemented in the |
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language of your choice. |
language of your choice. |
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<br>Here, a file is not 'just' a sequence of bytes or lines but a sequence of ''recods'' (structured data). The structure is usually described by declarations contained in an ''INCLUDE'' file (PL/I) or ''COPY BOOK'' (COBOL). |
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<br>The ''by name'' assignment is a little extra available in PL/I. |
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<br>Data conversions may be necessary (as shown here for data element ''c''. |
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=={{header|PL/I}}== |
=={{header|PL/I}}== |
Revision as of 06:25, 28 April 2015
Copy part of input records to an output file.
Show how file processing as known from PL/I or COBOL can be implemented in the
language of your choice.
Here, a file is not 'just' a sequence of bytes or lines but a sequence of recods (structured data). The structure is usually described by declarations contained in an INCLUDE file (PL/I) or COPY BOOK (COBOL).
The by name assignment is a little extra available in PL/I.
Data conversions may be necessary (as shown here for data element c.
PL/I
<lang pli>*process source attributes xref or(!);
copys: Proc Options(Main); Dcl 1 s1 unal, 2 a Char(5), 2 b Char(5), 2 c Bin Fixed(31), 2 d Char(5); Dcl 1 s2, 2 a Char(5), 2 c Pic'99', 2 x Char(5) Init('XXXXX'); Dcl o1 Record Output; /* create a test file */ Dcl in Record Input; Dcl out Record Output; Do i=1 To 5; s1.a=repeat('A',i); s1.b=repeat('B',i); s1.c=i; s1.d=repeat('D',i); Write File(o1) From(s1); End; Close File(o1);
On Endfile(in) Goto eoj; Do i=1 By 1; /* copy parts of the test file */ Read File(in) Into(s1); s2=s1, by name; /* only fields a and c are copied */ Write File(out) From(s2); End; eoj: End;
</lang>
- Output:
AA 01XXXXX AAA 02XXXXX AAAA 03XXXXX AAAAA04XXXXX AAAAA05XXXXX
Rexx
<lang rexx>in='in.txt' out='out.txt'; 'erase' out Do While lines(in)>0
l=linein(in) Parse Var l a +5 b +5 c +4 d +5 chex=c2x(c) cpic=left(chex,2) call lineout out,a||cpic||'XXXXX' End
Call lineout in Call lineout out 'type' out</lang>
- Output:
Using the test file produced by PL/I. The data conversion used for c is not very general!
AA 01XXXXX AAA 02XXXXX AAAA 03XXXXX AAAAA04XXXXX AAAAA05XXXXX