// This program implements the topological sort algorithm.  The prerequisite
//   relation is assumed to be stored explicitly in a file as a list of
//   task names, each occupying a single line.  The set of tasks is
//   assumed to be stored implicitly.  Its explicit representation as
//   an instance of the class "taskset" is constructed from the
//   components of the pairs of the relation.


#include <stdlib.h>
#include <string.h>
#include <iostream.h>
#include <fstream.h>
#include <assert.h>
#include "mytask4.h"


///////////////////////// MAIN PROGRAM /////////////////////////

// The main program merely creates an input stream given a file,
//   constructs a taskset given the input stream,
//   and topologically sorts the taskset to standard output

int main(void)                                                           {
ifstream istr;
taskset *s;
char filename[FILENMLEN];
    cout << "enter input file name:  ";
    cin >> filename;
    istr.open(filename);
    if (istr)					{
      s=new taskset(istr);
      if (!s->bad())
	s->topsort(cout);
      else
	cout << "ill-formed input" << endl;
      delete s;
      }
    else
      cout << "file not found" << endl;
  istr.close();
  return 0;
}