  plhist(n, data, datmin, datmax, nbin, oldwin)
  *********************************************

  plhist

  Plots a histogram from n data points stored in the array data. This
  routine bins the data into nbin bins equally spaced between datmin and
  datmax, and calls plbin to draw the resulting histogram. Parameter oldwin
  allows the histogram either to be plotted in an existing window or causes
  plhist to call plenv with suitable limits before plotting the histogram.

  n (PLINT, input): Number of data points.

  data (PLFLT *, input): Pointer to array with values of the n data
  points.

  datmin (PLFLT, input): Left-hand edge of lowest-valued bin.

  datmax (PLFLT, input): Right-hand edge of highest-valued bin.

  nbin (PLINT, input): Number of (equal-sized) bins into which to divide
  the interval xmin to xmax.

  oldwin (PLINT, input): If one, the histogram is plotted in the
  currently-defined window, and if zero, plenv is called automatically before
  plotting.

