Compile and Execute Pascal Online

uses crt;
var i, checkNum: integer;
fileIn, fileOut: text;

function isPrimeNumber(n: integer): boolean;
begin
    isPrimeNumber:= true;
    for i := 2 to round(sqrt(n)) do 
        if (n mod i > 0) isPrimeNumber := false;
end;

begin
    //Paralel file handling 
    assign(fileIn, 'SND.dat');
    assign(fileOut, 'DSNT.dat');
    
    reset(fileIn);
    rewrite(fileOut);
    
    while not eof(fileIn) do
        begin
            read(fileIn, checkNum);
            if (isPrimeNumber(checkNum) = true) then
                begin
                    write(checkNum);
                    write(' ');
                end;
        end;
    close(fileIn);
    close(fileOut);
end.