program flow has been kept as easy as possible with only a main loop that is repeated for each file given in the command line.

In pseudo code notation, the program flow is reduced to:

function main()
{
 print "presentation message";
 for each file specified in the command line
 {
   open file;
   parse json data from file;
   write json data to standard output;
   close file;
 }
 print "final statistics";
}