procedure main(A)

W := 50                         # avg width for histogram bar
B := 10                         # histogram bins
if *A = 0 then put(A,100)       # 100 if none specified

while N := get(A) do {          # once per argument
   write("\nN=",N)

   N := 0 < integer(N) | next   # skip if invalid

   stddev() # reset
   m := 0.
   H := list(B,0)               # Histogram of
   every i := 1 to N do {       # calc running ...
      s := stddev(r := ?0)      # ... std dev
      m +:= r/N                 # ... mean
      H[integer(*H*r)+1] +:= 1  # ... histogram
      }

   write("mean=",m)
   write("stddev=",s)
   every i := 1 to *H do        # show histogram
      write(right(real(i)/*H,5)," : ",repl("*",integer(*H*50./N*H[i])))
   }
end