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tell
Tristan Hume edited this page Apr 23, 2012
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#tell
##Syntax An tellStatement is:
tell : fileNumber , filePositionVar
##Description The tell statement sets filePositionVar, whose type must be int, to the current offset in bytes from the beginning of the specified file. The fileNumber must specify a file that is open with seek capability (or else a program argument file that is implicitly opened). The tell statement is useful for recording the file position of a certain piece of data for later access using seek.
##Example This example shows how to use tell to record the location of a record in a file. This location is later used by seek to allow the record to be read.
var employeeRecord :
record
name : string ( 30 )
pay : int
dept : 0 .. 9
end record
var fileNo : int
var location : int
open : fileNo, "payroll", write, seek
�
tell : fileNo, location % Make note of this location
write : fileNo, employeeRecord % Write record at this location
�
seek : fileNo, location % Go back to location
read : fileNo, employeeRecord % Read the record
% that was previously written
##See also the read.html, write.html, open.html, close.html, seek.html, get.html and put.html statements.