-Data-files
There are two data-files,as agreed on in the requirements. One datafile, 
containing the "raw" data, is a spreadsheet listing all the copies and 
their references, along with other useful information (not included in 
this document). The second data file is a summary report giving the var-
ious findings.

-Line number zero
In the raw data file, you may find references with line number zero and 
filename "NULL". These are references the compiler creates when breaking 
a single line of code into several lines, such as in "for" statements, 
or a sequence of assignments (x = y = 1). In the later case, it is equiv-
elant to:

y = 1;
x = y;

And the "y = 1" line is considered line number zero. I find no reason to 
believe that this creates any inaccuracies in the analysis.