Building a histogram from raw data

Write code that turns a list of numbers into a histogram.

Choose bins, then count in one pass. Fix the range $[\min,\max]$ and number of bins $m$ (width $w$), set up $m$ zero counters, and for each $x$ increment bin $\lfloor(x-\min)/w\rfloor$, clamping the top edge into the last bin and handling out-of-range values. This is $O(n)$ time and $O(m)$ space; discuss bin-width choice and normalising counts to a density.