; File: histo.pro
; Author: Erik Brisson

pro myhisto, xmin, xmax, nbins, y
    xspan = xmax - xmin
    bsize = float(xspan) / float(nbins) 
    print, "bsize =", bsize
    h = histogram(y, min=xmin, max=xmax, binsize=bsize)
    x = xmin + (findgen(nbins)+0.5)*bsize
    for i=0, nbins-1 do begin
	print, i, x(i), h(i)
    end
    plot, psym=10, x, h

; optional stuff to fill in the two ends
    xextra = [xmin, xmin, xmin+(bsize/2.0)]
    hextra = [0, h(0), h(0)];
    oplot, xextra, hextra
    xextra = [xmax-(bsize/2.0), xmax, xmax]
    hextra = [h(nbins-1), h(nbins-1), 0];
    oplot, xextra, hextra
end

x = findgen(101) - 50
y = x * sin(x)
xmin = -50
xmax = 50
nbins = 10

window, 0, retain=2, title='original function'
plot, x, y

window, 1, retain=2, title='myhisto'
myhisto, xmin, xmax, nbins, y

end