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Input loop: Difference between revisions
→[[Basic input loop#ALGOL 68]]
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=={{header|ALGOL 68}}==
For file consisting of just one page - a typical linux/unix file:
main:(
PROC raise logical file end = (REF FILE f) BOOL: ( except logical file end );
on logical file end(stand in, raise logical file end);
DO
print(read string);
read(new line);
print(new line)
OD;
except logical file end:
SKIP
)
For multi page files, each page is seekable with ''<code>PROC set = (REF FILE file, INT page, line, char)VOID: ~</code>''. This allows rudimentary random access where each new page is effectively a new record.
main:(
PROC raise logical file end = (REF FILE f) BOOL: ( except logical file end );
on logical file end(stand in, raise logical file end);
DO
PROC raise page end = (REF FILE f) BOOL: ( except page end );
on page end(stand in, raise page end);
DO
print(read string);
read(new line);
print(new line)
OD;
except page end:
read(new page);
print(new page)
OD;
except logical file end:
SKIP
)
The boolean functions ''physical file ended(f)'', ''logical file ended(f)'', ''page ended(f)'' and ''line ended(f)'' are also available to indicate the end of a file, page and line.
=={{header|AWK}}==
This just reads lines from stdin and prints them until EOF is read.
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