/* The code is developed from Cay S. Horstmann CCC text.  */
#include "mergeSortC.h"

MerSort::MerSort(int n, int max)
{
	rand_seed();
	int i;
	for(i=0; i<n; i++)
	{
		v.push_back(rand_int(1,max));
	}//end for

}//end constructor

void MerSort::merge(int from, int mid, int to)
{
    int i, j, k;
    int n = to - from + 1;
    vector<int> b(n); // temporary merge vector, sized just as needed

    for (k = 0, i = from, j = mid+1; i <= mid && j <= to; k++)
        if (v[i] < v[j]) // smallest goes first
           {	b[k] = v[i];
		i++;
	   }
        else
           {	 b[k] = v[j];
		j++;
	   }
    for (; i <= mid; i++, k++) // remaining elements from first half
        b[k] = v[i];
    for (; j <= to; j++, k++) // remaining elements from second half
        b[k] = v[j];

    for (k = 0; k < n; k++) // copy merged vector back to a
        v[k+from] = b[k];
} // merge

void MerSort::sort( ) { sort(0, v.size()-1); }

void MerSort::sort( int from, int to)
{
    int mid;

    if (from == to) return;

    mid = (from + to) / 2;
    sort(from, mid);
    sort(mid + 1, to);
    merge(from, mid, to);

} // mergeSort

void MerSort::read( )
{
   int datum;
   while( cin>> datum)
   	v.push_back(datum);
}//read
void MerSort::read( string & f)
{

   int datum;
	ifstream fs;
	fs.open(f.c_str());
	if(fs.fail()){
		cerr<< "Failed to open "<<f << " for input." <<endl;
		exit( EXIT_FAILURE);
	}//not cin

	   while( fs>> datum)
		v.push_back(datum);

   	fs.close();
} //read
void MerSort::print( )
{
      for(int i=0; i<v.size(); ++i)
   	cout<<v[i]<<endl;
}//print
void MerSort::print( string & f)
{
        ofstream fs;
	fs.open(f.c_str());
	if(fs.fail()){
		cerr<< "Failed to open "<<f << " for output." << endl;
		exit( EXIT_FAILURE);
	}

        for(int i=0; i<v.size(); ++i)
        	fs<<v[i]<<endl;

	fs.close();
}//print