4.3BSD/usr/contrib/icon/samples/diffwords.dat

procedure main()
   local limit, s, i
   limit := 100
   s := set([])
   every insert(s,1 to limit)
   every member(s,i := 2 to limit) do
      every delete(s,i + i to limit by i)
   primes := sort(s)
   write("There are ",*primes," primes in the first ",limit," integers.")
   write("The primes are:")
   every write(right(!primes,*limit + 1))
end