My main question is how to fix denc() in my code ?

An old irish joke goes "could you tell me the way to Tipperary?" - "well, I wouldn't start from here..."

Perhaps you may want to start with removing the bogus split in sub denc:

    open (DAT, "$INfile") || die "$!\n";
    my @aTd = <DAT>;
    close(DAT);
    @aTd = split(/\n/, "@aTd");
[download]

What is this supposed to do? Here's what it does: It opens a file, reads all lines into an array. Each line has a newline appended, since there's no chomp. The array is then interpolated into a string: the array elements are joined with blanks (the default value of the $" special variable), the resulting string is split at LF chars into the same array.

Which is a bizarre way to chop "\n" from all and prepend a blank to each element in @aTd except the first.

<update>

Perhaps you want this instead?

    open (DAT, "$INfile") || die "$!\n";
    chomp(my @aTd = <DAT>);
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</update>

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