indexx.cpp

VC常用数值算法集C7 ECLASS.CPP ECLAZZ.CPP INDEXX.CPP PIKSR2.CPP PIKSRT.CPP QCKSRT.CPP RANK.CPP SHELL

void indexx(int n, double arrin[], int indx[])
{
	int i,j,l,ir,indxt;
	double q;
    for (j = 1; j<=n; j++)
	{
        indx[j] = j;
    }
    if (n == 1)
	{
		return;
	}
    l = int(n / 2 + 1);
    ir = n;
    do
	{
		if (l > 1)
		{
			l = l - 1;
			indxt = indx[l];
			q = arrin[indxt];
		}
		else
		{
			indxt = indx[ir];
			q = arrin[indxt];
			indx[ir] = indx[1];
			ir = ir - 1;
			if (ir == 1)
			{
				indx[1] = indxt;
				return;
			}
		}
		i = l;
		j = l + l;
		while (j <= ir)
		{
			if (j < ir)
			{
            	if (arrin[indx[j]] < arrin[indx[j + 1]])
				{
					j = j + 1;
				}
			}
			if (q < arrin[indx[j]])
			{
				indx[i] = indx[j];
				i = j;
				j = j + j;
			}
			else
			{
				j = ir + 1;
			}
		}
		indx[i] = indxt;
    }while(1);
}