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Program Example37;
{ This program demonstrates the FileCreate/FileSeek/FileReed/FileTruncate functions }
Uses sysutils;
Var I,J,F : Longint;
Begin
F:=FileCreate ('test.dat');
If F=-1 then
Halt(1);
For I:=0 to 100 do
FileWrite(F,I,SizeOf(i));
FileClose(f);
F:=FileOpen ('test.dat',fmOpenRead);
For I:=0 to 100 do
begin
FileRead (F,J,SizeOF(J));
If J<>I then
Writeln ('Mismatch at file position ',I)
end;
FileSeek(F,0,fsFromBeginning);
Randomize;
Repeat
FileSeek(F,Random(100)*4,fsFromBeginning);
FileRead (F,J,SizeOf(J));
Writeln ('Random read : ',j);
Until J>80;
FileClose(F);
F:=FileOpen('test.dat',fmOpenWrite);
I:=50*SizeOf(Longint);
If FileTruncate(F,I) then
Writeln('SuccessFully truncated file to ',I,' bytes.');
FileClose(F);
End.
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